Foot presence sensing systems for active footwear

ABSTRACT

A foot presence sensor system for an active article of footwear can include a sensor housing configured to be disposed at or in an insole of the article, and a controller circuit, disposed within the sensor housing, configured to trigger one or more automated functions of the footwear based on a foot presence indication. In an example, the sensor system includes a capacitive sensor configured to sense changes in a capacitance signal in response to proximity of a body. A dielectric member can be provided between the capacitive sensor and the body to enhance an output signal from the sensor.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.15/460,060, filed Mar. 15, 2017, which application claims the benefit ofpriority of Walker et al., U.S. Provisional Patent Application Ser. No.62/308,657 (Attorney Docket No. 4228.054PRV), entitled “MAGNETIC ANDPRESSURE-BASED FOOT PRESENCE AND POSITION SENSING SYSTEMS AND METHODSFOR ACTIVE FOOTWEAR,” filed on Mar. 15, 2016, and of Walker et al., U.S.Provisional Patent Application Ser. No. 62/308,667 (Attorney Docket No.4228.074PRV), entitled “CAPACITIVE FOOT PRESENCE AND POSITION SENSINGSYSTEMS AND METHODS FOR ACTIVE FOOTWEAR,” filed on Mar. 15, 2016, and ofWalker, Steven H., U.S. Provisional Patent Application Ser. No.62/424,939 (Attorney Docket No. 4228.081PRV), entitled “CAPACITIVE FOOTPRESENCE SENSING FOR FOOTWEAR,” filed on Nov. 21, 2016, and of Walker,Steven H., U.S. Provisional Patent Application Ser. No. 62/424,959(Attorney Docket No. 4228.093PRV), entitled “FOOT PRESENCE AND IMPACTRATE OF CHANGE FOR ACTIVE FOOTWEAR,” filed on Nov. 21, 2016, each ofwhich is herein incorporated by reference.

BACKGROUND

Various shoe-based sensors have been proposed to monitor variousconditions. For example, Brown, in U.S. Pat. No. 5,929,332, titled“Sensor shoe for monitoring the condition of a foot”, provides severalexamples of shoe-based sensors. Brown mentions a foot force sensor caninclude an insole made of layers of relatively thin, planar, flexible,resilient, dielectric material. The foot force sensor can includeelectrically conductive interconnecting means that can have anelectrical resistance that changes based on an applied compressiveforce.

Brown further discusses a shoe to be worn by diabetic persons, orpersons afflicted with various types of foot maladies, where excesspressure exerted upon a portion of the foot tends to give rise toulceration. The shoe body can include a force sensing resistor (FSR),and a switching circuit coupled to the resistor can activate an alarmunit to warn a wearer that a threshold pressure level is reached orexceeded.

Devices for automatically tightening an article of footwear have beenpreviously proposed. Liu, in U.S. Pat. No. 6,691,433, titled “Automatictightening shoe”, provides a first fastener mounted on a shoe's upperportion, and a second fastener connected to a closure member and capableof removable engagement with the first fastener to retain the closuremember at a tightened state. Liu teaches a drive unit mounted in theheel portion of the sole. The drive unit includes a housing, a spoolrotatably mounted in the housing, a pair of pull strings and a motorunit. Each string has a first end connected to the spool and a secondend corresponding to a string hole in the second fastener. The motorunit is coupled to the spool. Liu teaches that the motor unit isoperable to drive rotation of the spool in the housing to wind the pullstrings on the spool for pulling the second fastener towards the firstfastener. Liu also teaches a guide tube unit that the pull strings canextend through.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 illustrates generally an exploded view of components of an activefootwear article, according to an example embodiment.

FIGS. 2A-2C illustrate generally a sensor system and motorized lacingengine, according to some example embodiments.

FIG. 3 illustrates generally a block diagram of components of amotorized lacing system, according to an example embodiment.

FIG. 4 is a diagram illustrating pressure distribution data for anominal or average foot (left) and for a high arch foot (right) in afootwear article when a user of a footwear article is standing.

FIGS. 5A and 5B illustrate generally diagrams of a capacitance-basedfoot presence sensor in an insole of a footwear article, according toexample embodiments.

FIG. 6 illustrates generally a capacitive sensor system for footpresence detection, according to an example embodiment.

FIG. 7 illustrates generally a schematic of a first capacitance-basedfoot presence sensor, according to an example embodiment.

FIG. 8 illustrates generally a schematic of a second capacitance-basedfoot presence sensor, according to an example embodiment.

FIGS. 9A, 9B, and 9C illustrate generally examples of capacitance-basedfoot presence sensor electrodes, according to some example embodiments.

FIG. 10 illustrates a flowchart showing an example of using footpresence information from a footwear sensor.

FIG. 11 illustrates a flowchart showing a second example of using footpresence information from a footwear sensor.

FIG. 12 illustrates generally a chart of first time-varying informationfrom a capacitive foot presence sensor.

FIG. 13 illustrates generally a chart of second time-varying informationfrom a capacitive foot presence sensor.

FIG. 14 illustrates generally a chart of third time-varying informationfrom a capacitive foot presence sensor.

FIG. 15 illustrates generally a chart of fourth time-varying informationfrom a capacitive foot presence sensor.

FIG. 16 illustrates generally a chart of time-varying information from acapacitive foot presence sensor and a signal morphology limit, accordingto an example embodiment.

FIG. 17 illustrates generally an example of a diagram of acapacitance-based foot presence sensor in a midsole of a footweararticle and located under a dielectric stack.

FIG. 18 illustrates generally an example that includes a chart showingan effect of the dielectric filler on a capacitance-indicating signalfrom the capacitive foot presence sensor.

FIG. 19 illustrates generally an example of a chart that shows a portionof a capacitance-indicating third signal from a capacitance-based footpresence sensor in footwear.

DETAILED DESCRIPTION

The concept of self-tightening shoelaces was first widely popularized bythe fictitious power-laced Nike® sneakers worn by Marty McFly in themovie Back to the Future II, which was released back in 1989. WhileNike® has since released at least one version of power-laced sneakerssimilar in appearance to the movie prop version from Back to the FutureII, the internal mechanical systems and surround footwear platformemployed do not necessarily lend themselves to mass production or dailyuse. Additionally, previous designs for motorized lacing systemscomparatively suffered from problems such as high cost of manufacture,complexity, assembly challenges, lack of serviceability, and weak orfragile mechanical mechanisms, to highlight just a few of the manyissues. The present inventors have developed a modular footwear platformto accommodate motorized and non-motorized lacing engines that solvessome or all of the problems discussed above, among others. Thecomponents discussed below provide various benefits including, but notlimited to, serviceable components, interchangeable automated lacingengines, robust mechanical design, robust control algorithms, reliableoperation, streamlined assembly processes, and retail-levelcustomization. Various other benefits of the components described belowwill be evident to persons of skill in the relevant arts.

In an example, a modular automated lacing footwear platform includes amid-sole plate secured to a mid-sole in a footwear article for receivinga lacing engine. The design of the mid-sole plate allows a lacing engineto be added to the footwear platform as late as at a point of purchase.The mid-sole plate, and other aspects of the modular automated footwearplatform, allow for different types of lacing engines to be usedinterchangeably. For example, the motorized lacing engine discussedbelow could be changed out for a human-powered lacing engine.Alternatively, a fully-automatic motorized lacing engine with footpresence sensing or other features can be accommodated within thestandard mid-sole plate.

The automated footwear platform discussed herein can include an outsoleactuator interface to provide tightening control to the end user as wellas visual feedback, for example, using LED lighting projected throughtranslucent protective outsole materials. The actuator can providetactile and visual feedback to the user to indicate status of the lacingengine or other automated footwear platform components.

In an example, the footwear platform includes a foot presence sensorconfigured to detect when a foot is present in the shoe. When a foot isdetected, then one or more footwear functions or processes can beinitiated, such as automatically and without a further user input orcommand. For example, upon detection that a foot is properly seated inthe footwear against an insole, a control circuit can automaticallyinitiate lace tightening, data collection, footwear diagnostics, orother processes.

Prematurely activating or initiating an automated lacing or footweartightening mechanism can detract from a user's experience with thefootwear. For example, if a lacing engine is activated before a foot iscompletely seated against an insole, then the user may have a difficulttime getting a remainder of his or her foot into the footwear, or theuser may have to manually adjust a lacing tension. The present inventorshave thus recognized that a problem to be solved includes determiningwhether a foot is seated properly or fully in a footwear article, suchas with toe, mid-sole, and heel portions properly aligned withcorresponding portions of an insole. The inventors have furtherrecognized that the problem includes accurately determining a footlocation or foot orientation using as few sensors as possible, such asto reduce sensor costs and assembly costs, and to reduce devicecomplexity.

A solution to these problems includes providing a sensor in an archand/or heel region of the footwear. In an example, the sensor is acapacitive sensor that is configured to sense changes in a nearbyelectric field. Changes in the electric field, or capacitance changes,can be realized as a foot enters or exits the footwear, including whilesome portions of the foot are at a greater distance from the sensor thanother portions of the foot. In an example, the capacitive sensor isintegrated with or housed within a lacing engine enclosure. In anexample, at least a portion of the capacitive sensor is provided outsideof the lacing engine enclosure and includes one or more conductiveinterconnects to power or processing circuitry inside the enclosure.

A capacitive sensor suitable for use in foot presence detection can havevarious configurations. The capacitive sensor can include a platecapacitor wherein one plate is configured to move relative to another,such as in response to pressure or to a change of pressure exerted onone or more of the plates. In an example, the capacitive sensor includesmultiple traces, such as arranged substantially in a plane that isparallel to or coincident with an upper surface of an insole. Suchtraces can be laterally separated by an air gap (or other material, suchas Styrofoam) and can be driven selectively or periodically by an ACdrive signal provided by an excitation circuit. In an example, theelectrodes can have an interleaved, comb configuration. Such acapacitive sensor can provide a changing capacitance signal that isbased on movement of the electrodes themselves relative to one anotherand based on interference of the electric field near the electrodes dueto presence or absence or movement of a foot or other object.

In an example, a capacitance-based sensor can be more reliable than amechanical sensor, for example, because the capacitance-based sensorneed not include moving parts. Electrodes of a capacitance-based sensorcan be coated or covered by a durable, electric field-permeablematerial, and thus the electrodes can be protected from direct exposureto environmental changes, wetness, spillages, dirt, or othercontaminating agents, and humans or other materials are not in directcontact with the sensor's electrodes.

In an example, the capacitive sensor provides an analog output signalindicative of a magnitude of a capacitance, or indicative of a change ofcapacitance, that is detected by the sensor. The output signal can havea first value corresponding to a low capacitance) when a foot is presentnear the sensor, and the output signal have a different second value(e.g., corresponding to a high capacitance) when a foot is absent.

In an example, the output signal when the foot is present can providefurther information. For example, there can be a detectable variation inthe capacitance signal that correlates to step events. In addition,there can be a detectable long-term drift in the capacitance signal thatcan indicate wear-and-tear and/or remaining life in shoe components likeinsoles, orthotics, or other components.

In an example, the capacitive sensor includes or is coupled to acapacitance-to-digital converter circuit configured to provide a digitalsignal indicative of a magnitude of a capacitance sensed by the sensor.In an example, the capacitive sensor includes a processor circuitconfigured to provide an interrupt signal or logic signal that indicateswhether a sensed capacitance value meets a specified thresholdcapacitance condition. In an example, the capacitive sensor measures acapacitance characteristic relative to a baseline or referencecapacitance value, and the baseline or reference can be updated oradjusted such as to accommodate environment changes or other changesthat can influence sensed capacitance values.

In an example, a capacitive sensor is provided under-foot near an archor heel region of an insole of a shoe. The capacitive sensor can besubstantially planar or flat. The capacitive sensor can be rigid orflexible and configured to conform to contours of a foot. In some cases,an air gap, such as can have a relatively low dielectric constant or lowrelative permittivity, can exist between a portion of the capacitivesensor and the foot when the shoe is worn. A gap filler, such as canhave a relatively high dielectric constant or greater relativepermittivity than air, can be provided above the capacitive sensor inorder to bridge any airspace between the capacitive sensor and a footsurface. The gap filler can be compressible or incompressible. In anexample, the gap filler is selected to provide a suitable compromisebetween dielectric value and suitability for use in footwear in order toprovide a sensor with adequate sensitivity and user comfort under foot.

The following discusses various components of an automated footwearplatform including a motorized lacing engine, a foot presence sensor, amid-sole plate, and various other components of the platform. While muchof this disclosure focuses on foot presence sensing as a trigger for amotorized lacing engine, many aspects of the discussed designs areapplicable to a human-powered lacing engine, or other circuits orfeatures that can interface with a foot presence sensor, such as toautomate other footwear functions like data collection or physiologicmonitoring. The term “automated,” such as used in “automated footwearplatform,” is not intended to cover only a system that operates withouta specified user input. Rather, the term “automated footwear platform”can include various electrically powered and human-powered,automatically activated and human activated, mechanisms for tightening alacing or retention system of the footwear, or for controlling otheraspects of active footwear.

FIG. 1 illustrates generally an exploded view of components of an activefootwear article, according to an example embodiment. The example ofFIG. 1 includes a motorized lacing system 100 with a lacing engine 110,a lid 120, an actuator 130, a mid-sole plate 140, a mid-sole 155, and anoutsole 165. The lacing engine 110 can include a user-replaceablecomponent in the system 100, and can include or can be coupled to one ormore foot presence sensors. In an example, the lacing engine 110includes, or is coupled to, a capacitive foot presence sensor. Thecapacitive foot presence sensor, not shown in the example of FIG. 1, caninclude multiple electrodes arranged on a foot-facing side of the lacingengine 110. In an example, the electrodes of the capacitive footpresence sensor can be housed within the lacing engine 110, can beintegrated with the housing of the lacing engine 110, or can be disposedelsewhere near the lacing engine 110 and coupled to power or processingcircuitry inside of the lacing engine 110 using one or more electricalconductors.

Assembling the motorized lacing system 100 in the example of FIG. 1starts with securing the mid-sole plate 140 within the mid-sole 155.Next, the actuator 130 can be inserted into an opening in a lateral sideof the mid-sole plate 140, such as opposite to interface buttons thatcan be embedded in the outsole 165. Next, the lacing engine 110 can beinserted into the mid-sole plate 140. In an example, the lacing engine110 can be coupled with one or more sensors that are disposed elsewherein the footwear. Other assembly methods can be similarly performed toconstruct the motorized lacing system 100.

In an example, the lacing system 100 is inserted under a continuous loopof lacing cable and the lacing cable is aligned with a spool in thelacing engine 110. To complete the assembly, the lid 120 can be insertedinto securing means in the mid-sole plate 140, secured into a closedposition, and latched into a recess in the mid-sole plate 140. The lid120 can capture the lacing engine 110 and can assist in maintainingalignment of a lacing cable during operation.

The mid-sole plate 140 includes a lacing engine cavity 141, medial andlateral lace guides 142, an anterior flange 143, a posterior flange 144,superior (top) and inferior (bottom) surfaces, and an actuator cutout145. The lacing engine cavity 141 is configured to receive the lacingengine 110. In this example, the lacing engine cavity 141 retains thelacing engine 110 in lateral and anterior/posterior directions, but doesnot include a feature to lock the lacing engine 110 into the cavity 141.Optionally, the lacing engine cavity 141 includes detents, tabs, orother mechanical features along one or more sidewalls to more positivelyretain the lacing engine 110 within the lacing engine cavity 141.

The lace guides 142 can assist in guiding a lacing cable into positionwith the lacing engine 110. The lace guides 142 can include chamferededges and inferiorly slated ramps to assist in guiding a lacing cableinto a desired position with respect to the lacing engine 110. In thisexample, the lace guides 142 include openings in the sides of themid-sole plate 140 that are many times wider than a typical lacing cablediameter, however other dimensions can be used.

In the example of FIG. 1, the mid-sole plate 140 includes a sculpted orcontoured anterior flange 143 that extends further on a medial side ofthe mid-sole plate 140. The example anterior flange 143 is designed toprovide additional support under the arch of the footwear platform.However, in other examples the anterior flange 143 may be lesspronounced on the medial side. In this example, the posterior flange 144includes a contour with extended portions on both medial and lateralsides. The illustrated posterior flange 144 can provide enhanced lateralstability for the lacing engine 110.

In an example, one or more electrodes can be embedded in or disposed onthe mid-sole plate 140, and can form a portion of a foot presencesensor, such as a portion of a capacitive foot presence sensor. In anexample, the lacing engine 110 includes a sensor circuit that iselectrically coupled to the one or more electrodes on the mid-sole plate140. The sensor circuit can be configured to use electric field orcapacitance information sensed from the electrodes to determine whethera foot is present or absent in a region adjacent to the mid-sole plate140. In an example, the electrodes extend from an anterior-most edge ofthe anterior flange 143 to a posterior-most edge of the posterior flange144, and in other examples the electrodes extend over only part of oneor both of the flanges.

In an example, the footwear or the motorized lacing system 100 includesor interfaces with one or more sensors that can monitor or determine afoot presence in the footwear, foot absence from the footwear, or footposition characteristic within the footwear. Based on information fromone or more such foot presence sensors, the footwear including themotorized lacing system 100 can be configured to perform variousfunctions. For example, a foot presence sensor can be configured toprovide binary information about whether a foot is present or notpresent in the footwear. In an example, a processor circuit coupled tothe foot presence sensor receives and interprets digital or analogsignal information and provides the binary information about whether afoot is present or not present in the footwear. If a binary signal fromthe foot presence sensor indicates that a foot is present, then thelacing engine 110 in the motorized lacing system 100 can be activated,such as to automatically increase or decrease a tension on a lacingcable, or other footwear constricting means, such as to tighten or relaxthe footwear about a foot. In an example, the lacing engine 110, orother portion of a footwear article, includes a processor circuit thatcan receive or interpret signals from a foot presence sensor.

In an example, a foot presence sensor can be configured to provideinformation about a location of a foot as it enters footwear. Themotorized lacing system 100 can generally be activated, such as totighten a lacing cable, only when a foot is appropriately positioned orseated in the footwear, such as against all or a portion of the footweararticle's insole. A foot presence sensor that senses information about afoot travel or location can provide information about whether a foot isfully or partially seated such as relative to an insole or relative tosome other feature of the footwear article. Automated lacing procedurescan be interrupted or delayed until information from the sensorindicates that a foot is in a proper position.

In an example, a foot presence sensor can be configured to provideinformation about a relative location of a foot inside of footwear. Forexample, the foot presence sensor can be configured to sense whether thefootwear is a good “fit” for a given foot, such as by determining arelative position of one or more of a foot's arch, heel, toe, or othercomponent, such as relative to the corresponding portions of thefootwear that are configured to receive such foot components. In anexample, the foot presence sensor can be configured to sense whether aposition of a foot or a foot component changes over time relative to aspecified or previously-recorded reference position, such as due toloosening of a lacing cable over time, or due to natural expansion andcontraction of a foot itself.

In an example, a foot presence sensor can include an electrical,magnetic, thermal, capacitive, pressure, optical, or other sensor devicethat can be configured to sense or receive information about a presenceof a body. For example, an electrical sensor can include an impedancesensor that is configured to measure an impedance characteristic betweenat least two electrodes. When a body such as a foot is located proximalor adjacent to the electrodes, the electrical sensor can provide asensor signal having a first value, and when a body is located remotelyfrom the electrodes, the electrical sensor can provide a sensor signalhaving a different second value. For example, a first impedance valuecan be associated with an empty footwear condition, and a lesser secondimpedance value can be associated with an occupied footwear condition.

An electrical sensor can include an AC signal generator circuit and anantenna that is configured to emit or receive high frequency signalinformation, such as including radio frequency information. Based onproximity of a body relative to the antenna, one or more electricalsignal characteristics, such as impedance, frequency, or signalamplitude, can be received and analyzed to determine whether a body ispresent. In an example, a received signal strength indicator (RSSI)provides information about a power level in a received radio signal.Changes in the RSSI, such as relative to some baseline or referencevalue, can be used to identify a presence or absence of a body. In anexample, WiFi frequencies can be used, for example in one or more of 2.4GHz, 3.6 GHz, 4.9 GHz, 5 GHz, and 5.9 GHz bands. In an example,frequencies in the kilohertz range can be used, for example, around 400kHz. In an example, power signal changes can be detected in milliwatt ormicrowatt ranges.

A foot presence sensor can include a magnetic sensor. A first magneticsensor can include a magnet and a magnetometer. In an example, amagnetometer can be positioned in or near the lacing engine 110. Amagnet can be located remotely from the lacing engine 110, such as in asecondary sole, or insole, that is configured to be worn above theoutsole 165. In an example, the magnet is embedded in foam or in anothercompressible material of the secondary sole. As a user depresses thesecondary sole such as when standing or walking, corresponding changesin the location of the magnet relative to the magnetometer can be sensedand reported via a sensor signal.

A second magnetic sensor can include a magnetic field sensor that isconfigured to sense changes or interruptions (e.g., via the Hall effect)in a magnetic field. When a body is proximal to the second magneticsensor, the sensor can generate a signal that indicates a change to anambient magnetic field. For example, the second magnetic sensor caninclude a Hall effect sensor that varies a voltage output signal inresponse to variations in a detected magnetic field. Voltage changes atthe output signal can be due to production of a voltage differenceacross an electric signal conductor, such as transverse to an electriccurrent in the conductor and a magnetic field perpendicular to thecurrent.

In an example, the second magnetic sensor is configured to receive anelectromagnetic field signal from a body. For example, Varshavsky etal., in U.S. Pat. No. 8,752,200, titled “Devices, systems and methodsfor security using magnetic field based identification”, teaches using abody's unique electromagnetic signature for authentication. In anexample, a magnetic sensor in a footwear article can be used toauthenticate or verify that a present user is a shoe's owner via adetected electromagnetic signature, and that the article should laceautomatically, such as according to one or more specified lacingpreferences (e.g., tightness profile) of the owner.

In an example, a foot presence sensor includes a thermal sensor that isconfigured to sense a change in temperature in or near a portion of thefootwear. When a wearer's foot enters a footwear article, the article'sinternal temperature changes when the wearer's own body temperaturediffers from an ambient temperature of the footwear article. Thus thethermal sensor can provide an indication that a foot is likely to bepresent or not based on a temperature change.

In an example, a foot presence sensor includes a capacitive sensor thatis configured to sense a change in capacitance. The capacitive sensorcan include a single plate or electrode, or the capacitive sensor caninclude a multiple-plate or multiple-electrode configuration. Variousexamples of capacitive-type foot presence sensors are further describedherein.

In an example, a foot presence sensor includes an optical sensor. Theoptical sensor can be configured to determine whether a line-of-sight isinterrupted, such as between opposite sides of a footwear cavity. In anexample, the optical sensor includes a light sensor that can be coveredby a foot when the foot is inserted into the footwear. When the sensorindicates a change in a sensed light or brightness condition, anindication of a foot presence or position can be provided.

Any of the different types of foot presence sensors discussed herein canbe used independently, or information from two or more different sensorsor sensor types can be used together to provide more information about afoot presence, absence, orientation, goodness-of-fit with the footwear,or other information about a foot and/or its relationship with thefootwear.

FIGS. 2A-2C illustrate generally a sensor system and motorized lacingengine, according to some example embodiments. FIG. 2A introducesvarious external features of an example lacing engine 110, including ahousing structure 150, case screw 108, lace channel 112 (also referredto as lace guide relief 112), lace channel transition 114, spool recess115, button openings 122, buttons 121, button membrane seal 124,programming header 128, spool 131, and lace groove 132 in the spool 131.Other designs can similarly be used. For example, other switch types canbe used, such as sealed dome switches, or the membrane seal 124 can beeliminated, etc. In an example, the lacing engine 110 can include one ormore interconnects or electrical contacts for interfacing circuitryinternal to the lacing engine 110 with circuitry outside of the lacingengine 110, such as an external foot presence sensor (or componentthereof), an external actuator like a switch or button, or other devicesor components.

The lacing engine 110 can be held together by one or more screws, suchas the case screw 108. The case screw 108 can be positioned near theprimary drive mechanisms to enhance structural integrity of the lacingengine 110. The case screw 108 also functions to assist the assemblyprocess, such as holding the housing structure 150 together forultra-sonic welding of exterior seams.

In the example of FIG. 2A, the lacing engine 110 includes the lacechannel 112 to receive a lace or lace cable once the engine is assembledinto the automated footwear platform. The lace channel 112 can include achannel wall with chamfered edges to provide a smooth guiding surfaceagainst or within which a lace cable can travel during operation. Partof the smooth guiding surface of the lace channel 112 can include achannel transition 114, which can be a widened portion of the lacechannel 112 leading into the spool recess 115. The spool recess 115transitions from the channel transition 114 into generally circularsections that conform closely to a profile of the spool 131. The spoolrecess 115 can assist in retaining a spooled lace cable, as well as inretaining a position of the spool 131. Other aspects of the design canprovide other means to retain the spool 131. In the example of FIG. 2A,the spool 131 is shaped similarly to half of a yo-yo with a lace groove132 running through a flat top surface and a spool shaft (not shown inFIG. 2A) extending inferiorly from the opposite side.

A lateral side of the lacing engine 110 includes button openings 122that house buttons 121 that can be configured to activate or adjust oneor more features of the automated footwear platform. The buttons 121 canprovide an external interface for activation of various switchesincluded in the lacing engine 110. In some examples, the housingstructure 150 includes a button membrane seal 124 to provide protectionfrom dirt and water. In this example, the button membrane seal 124 is upto a few mils (thousandths of an inch) thick clear plastic (or similarmaterial) that can be adhered from a superior surface of the housingstructure 150, such as over a corner and down a lateral side. In anotherexample, the button membrane seal 124 is an approximately 2-mil thickvinyl adhesive backed membrane covering the buttons 121 and buttonopenings 122. Other types of buttons and sealants can be similarly used.

FIG. 2B is an illustration of housing structure 150 including a topsection 102 and a bottom section 104. In this example, the top section102 includes features such as the case screw 108, lace channel 112, lacechannel transition 114, spool recess 115, button openings 122, and abutton seal recess 126. In an example, the button seal recess 126 is aportion of the top section 102 that is relieved to provide an inset forthe button membrane seal 124.

In the example of FIG. 2B, the bottom section 104 includes features suchas a wireless charger access 105, a joint 106, and a grease isolationwall 109. Also illustrated, but not specifically identified, is the casescrew base for receiving case screw 108, as well as various featureswithin the grease isolation wall 109 for holding portions of a drivemechanism. The grease isolation wall 109 is designed to retain grease,or similar compounds surrounding the drive mechanism, away from variouselectrical components of the lacing engine 110.

The housing structure 150 can include, in one or both of the top andbottom sections 102 and 104, one or more electrodes 170 embedded in orapplied on a structure surface. The electrodes 170 in the example ofFIG. 2B are shown coupled to the bottom section 104. In an example, theelectrodes 170 comprise a portion of a capacitance-based foot presencesensor circuit see, e.g., the foot presence sensor 310 discussedherein). Additionally or alternatively, the electrodes 170 can becoupled to the top section 102. Electrodes 170 coupled to the top orbottom sections 102 or 104 can be used for wireless power transferand/or as a portion of a capacitance-based foot presence sensor circuit.In an example, the electrodes 170 include one or more portions that aredisposed on an outside surface of the housing structure 150, and inanother example the electrodes 170 include one or more portions that aredisposed on an inside surface of the housing structure 150,

FIG. 2C is an illustration of various internal components of lacingengine 110, according to an example embodiment. In this example, thelacing engine 110 further includes a spool magnet 136, O-ring seal 138,worm drive 140, bushing 141, worm drive key, gear box 148, gear motor145, motor encoder 146, motor circuit board 147, worm gear 151, circuitboard 160, motor header 161, battery connection 162, and wired chargingheader 163. The spool magnet 136 assists in tracking movement of thespool 131 though detection by a magnetometer (not shown in FIG. 2C). Theo-ring seal 138 functions to seal out dirt and moisture that couldmigrate into the lacing engine 110 around the spool shaft. The circuitboard 160 can include one or more interfaces or interconnects for a footpresence sensor, such as the capacitive foot presence sensor 310described below. In an example, the circuit board 160 includes one ormore traces or conductive planes that provide a portion of the footpresence sensor 310.

In this example, major drive components of the lacing engine 110 includethe worm drive 140, worm gear 151, gear motor 145 and gear box 148. Theworm gear 151 is designed to inhibit back driving of the worm drive 140and gear motor 145, which means the major input forces coming in fromthe lacing cable via the spool 131 can be resolved on the comparativelylarge worm gear and worm drive teeth. This arrangement protects the gearbox 148 from needing to include gears of sufficient strength towithstand both the dynamic loading from active use of the footwearplatform or tightening loading from tightening the lacing system. Theworm drive 140 includes additional features to assist in protectingvarious fragile portions of the drive system, such as the worm drivekey. In this example, the worm drive key is a radial slot in the motorend of the worm drive 140 that interfaces with a pin through the driveshaft coming out of the gear box 148. This arrangement prevents the wormdrive 140 from imparting undue axial forces on the gear box 148 or gearmotor 145 by allowing the worm drive 140 to move freely in an axialdirection (away from the gear box 148), transferring those axial loadsonto bushing 141 and the housing structure 150.

FIG. 3 illustrates generally a block diagram of components of amotorized lacing system 300, according to an example embodiment. Thesystem 300 includes some, but not necessarily all, components of amotorized lacing system such as including interface buttons 301, acapacitive foot presence sensor 310, and the housing structure 150enclosing a printed circuit board assembly (PCA) with a processorcircuit 320, a battery 321, a charging coil 322, an encoder 325, amotion sensor 324, and a drive mechanism 340. The drive mechanism 340can include, among other things, a motor 341, a transmission 342, and alace spool 343. The motion sensor 324 can include, among other things, asingle or multiple axis accelerometer, a magnetometer, a gyrometer, orother sensor or device configured to sense motion of the housingstructure 150, or of one or more components within or coupled to thehousing structure 150.

In the example of FIG. 3, the processor circuit 320 is in data or powersignal communication with one or more of the interface buttons 301, footpresence sensor 310, battery 321, charging coil 322, and drive mechanism340. The transmission 342 couples the motor 341 to the spool 343 to formthe drive mechanism 340. In the example of FIG. 3, the buttons 301, footpresence sensor 310, and environment sensor 350 are shown outside of, orpartially outside of, the housing structure 150.

In alternative embodiments, one or more of the buttons 301, footpresence sensor 310, and environment sensor 350 can be enclosed in thehousing structure 150. In an example, the foot presence sensor 310 isdisposed inside of the housing structure 150 to protect the sensor fromperspiration and dirt or debris. Minimizing or eliminating connectionsthrough the walls of the housing structure 150 can help increasedurability and reliability of the assembly.

In an example, the processor circuit 320 controls one or more aspects ofthe drive mechanism 340. For example, the processor circuit 320 can beconfigured to receive information from the buttons 301 and/or from thefoot presence sensor 310 and/or from the motion sensor 324 and, inresponse, control the drive mechanism 340, such as to tighten or loosenfootwear about a foot. In an example, the processor circuit 320 isadditionally or alternatively configured to issue commands to obtain orrecord sensor information, from the foot presence sensor 310 or othersensor, among other functions. In an example, the processor circuit 320conditions operation of the drive mechanism 340 on one or more ofdetecting a foot presence using the foot presence sensor 310, detectinga foot orientation or location using the foot presence sensor 310, ordetecting a specified gesture using the motion sensor 324.

In an example, the system 300 includes an environment sensor 350.Information from the environment sensor 350 can be used to update oradjust a baseline or reference value for the foot presence sensor 310.As further explained below, capacitance values measured by a capacitivefoot presence sensor can vary over time, such as in response to ambientconditions near the sensor. Using information from the environmentsensor 350, the processor circuit 320 and/or the foot presence sensor310 can therefore be configured to update or adjust a measured or sensedcapacitance value.

FIG. 4 is a diagram illustrating pressure distribution data for anominal or average foot (left) and for a high arch foot (right) in afootwear article 400 when a user of a footwear article is standing. Inthis example, it can be seen that the relatively greater areas ofpressure underfoot include at a heel region 401, at a ball region 402(e.g., between the arch and toes), and at a hallux region 403 (e.g., a“big toe” region). As discussed above, however, it can be advantageousto include various active components (e.g., including the foot presencesensor 310) in a centralized region, such as at or near an arch region.In an example, in the arch region, the housing structure 150 can begenerally less noticeable or intrusive to a user when a footwear articlethat includes the housing structure 150 is worn.

In the example of FIG. 4, the lacing engine cavity 141 can be providedin an arch region. One or more electrodes corresponding to the footpresence sensor 310 can be positioned at or near a first location 405.Capacitance values measured using the electrodes positioned at the firstlocation 405 can be different depending on the proximity of a footrelative to the first location 405. For example, different capacitancevalues would be obtained for the average foot and the high arch footbecause a surface of the foot itself resides at a different distancefrom the first location 405. In an example, a location of the footpresence sensor 310 and/or the lacing engine 110 can be adjustedrelative to footwear (e.g., by a user or by a technician at a point ofsale), such as to accommodate different foot characteristics ofdifferent users and to enhance a signal quality obtained from the footpresence sensor 310. In an example, a sensitivity of the foot presencesensor 310 can be adjusted, such as by increasing a drive signal levelor by changing a dielectric material positioned between the footpresence sensor 310 and the foot.

FIGS. 5A and 5B illustrate generally diagrams of a capacitance-basedfoot presence sensor in an insole of a footwear article, according toexample embodiments. The capacitance-based foot presence sensor can beprovided below a surface of an object or body 550, such as a foot, whenthe article incorporating the sensor is worn.

In FIG. 5A, the capacitance-based foot presence sensor can include afirst electrode assembly 501A coupled to a capacitive sensing controllercircuit 502. In an example, the controller circuit 502 is included in orincludes functions performed by the processor circuit 320. In theexample of FIG. 5A, the first electrode assembly 501A and/or thecontroller circuit 502 can be included in or mounted to an inner portionof the housing structure 150, or can be coupled to the PCA inside of thehousing structure 150. In an example, the first electrode assembly 501Acan be disposed at or adjacent to a foot-facing surface of the housingstructure 150. In an example, the first electrode assembly 501A includesmultiple traces distributed across an internal, upper surface region ofthe housing structure 150.

In FIG. 5B, the capacitance-based foot presence sensor can include asecond electrode assembly 501B coupled to the capacitive sensingcontroller circuit 502. The second electrode assembly 501B can bemounted to or near an outer portion of the housing structure 150, andcan be electrically coupled to the PCA inside of the housing structure150, such as using a flexible connector 511. In an example, the secondelectrode assembly 501B can be disposed at or adjacent to a foot-facingsurface of the housing structure 150. In an example, the secondelectrode assembly 501B includes a flexible circuit that is secured toan inner or outer surface of the housing structure 150, and coupled tothe processor circuit 320 via one or more conductors.

In an example, the controller circuit 502 includes an AtmelATSAML21E18B-MU, ST Microelectronics STM32L476M, or other similardevice. The controller circuit 502 can be configured to, among otherthings, provide an AC drive signal to at least a pair of electrodes inthe first or second electrode assembly 501A or 501B and, in response,sense changes in an electric field based on corresponding changes inproximity of the object or body 550 to the pair of electrodes, asexplained in greater detail below. In an example, the controller circuit502 includes or uses the foot presence sensor 310 or the processorcircuit 320.

Various materials can be provided between the electrode assembly 501 andthe object or body 550 to be sensed. For example, electrode insulation,a material of the housing structure 150, an insole material, an insertmaterial 510, a sock or other foot cover, body tape, kinesiology tape,or other materials can be interposed between the body 550 and theelectrode assembly 501, such as to change a dielectric characteristic ofthe footwear and thereby influence a capacitance detection sensitivityof a sensor that includes or uses the electrode assembly 501. Thecontroller circuit 502 can be configured to update or adjust anexcitation or sensing parameter based on the number or type ofinterposed materials, such as to enhance a sensitivity orsignal-to-noise ratio of capacitance values sensed using the electrodeassembly 501.

In the example of FIG. 5, the first and/or second electrode assembly501A and/or 501B can be excited by a signal generator in the controllercircuit 502, and as a result an electric field can project from a top,foot-facing side of the electrode assembly. In an example, an electricfield below the electrode assembly can be blocked at least in part usinga driven shield positioned below the sensing electrode. The drivenshield and electrode assembly can be electrically insulated from eachother. For example, if the first electrode assembly 501A is on onesurface of the PCA then the driven shield can be on the bottom layer ofthe PCA, or on any one of multiple inner layers on a multi-layer PCA. Inan example, the driven shield can be of equal or greater surface area ofthe first electrode assembly 501A, and can be centered directly belowthe first electrode assembly 501A. The driven shield can receive a drivesignal and, in response, generate an electric field of the samepolarity, phase and/or amplitude of an X axis leg of the field generatedby the first electrode assembly 501A. The driven shield's field canrepel the electric field of the first electrode assembly 501A, therebyisolating the sensor field from various parasitic effects, such asundesired coupling to a ground plane of the PCA. A driven shield can besimilarly provided for use with the second electrode assembly 501B. Forexample, the second electrode assembly 501B can be provided above thehousing structure 150 as shown in the example of FIG. 5B, and a portionof the housing structure 150 can include a conductive film that is usedas the driven shield. Additionally or alternatively, the driven shieldcan be provided elsewhere in the footwear article when the secondelectrode assembly 501B is provided at a location other than atop thehousing structure 150.

A preferred position in which to locate the housing structure 150 is inan arch area of footwear because it is an area less likely to be felt bya wearer and is less likely to cause discomfort to a wearer. Oneadvantage of using capacitive sensing for detecting foot presence infootwear includes that a capacitive sensor can function well even when acapacitive sensor is placed in an arch region and a user has arelatively or unusually high foot arch. For example, a sensor drivesignal amplitude or morphology characteristic can be changed or selectedbased on a detected signal-to-noise ratio of a signal received from acapacitive sensor. In an example, the sensor drive signal can be updatedor adjusted each time footwear is used, such as to accommodate changesin one or more materials (e.g., socks, insoles, etc.) disposed betweenthe first or second electrode assembly 501A or 501B and the body 550.

In an example, an electrode assembly of a capacitive sensor, such as thefirst or second electrode assembly 501A or 501B, can be configured tosense a difference in signals between multiple electrodes, such asbetween X and Y-axis oriented electrodes. In an example, a suitablesampling frequency can be between about 2 and 50 Hz. In sonic examples,capacitance-based foot sensing techniques can be relatively invariant toperspiration (wetness) on the insole or in a sock around a foot. Theeffect of such moisture can be to reduce a dynamic range of thedetection since the presence of moisture can increase a measuredcapacitance. However, in some examples, the dynamic range is sufficientto accommodate this effect within expected levels of moisture infootwear.

FIG. 6 illustrates generally a capacitive sensor system 600 for footpresence detection, according to an example embodiment. The system 600includes the body 550 (e.g., representing a foot in or near an activefootwear article) and first and second electrodes 601 and 602. Theelectrodes 601 and 602 can form all or a portion of the first or secondelectrode assembly 501A or 501B from the example of FIG. 5, such ascomprising a portion of the foot presence sensor 310. In the example ofFIG. 6, the first and second electrodes 601 and 602 are illustrated asbeing vertically spaced relative to one another and the body 550,however, the electrodes can similarly be horizontally spaced, forexample, as detailed in the example of FIGS. 7-9C. That is, in anexample, the electrodes can be disposed in a plane that is parallel to alower surface of the body 550. In the example of FIG. 6, the firstelectrode 601 is configured as a transmit electrode and is coupled to asignal generator 610. In an example, the signal generator 610 comprisesa portion of the processor circuit 320 from the example of FIG. 3. Thatis, the processor circuit 320 can be configured to generate a drivesignal and apply it to the first electrode 601.

As a result of exciting the first electrode 601 with a drive signal fromthe signal generator 610, an electric field 615 can be generatedprimarily between the first and second electrodes 601 and 602. That is,various components of the generated electric field 615 can extendbetween the first and second electrodes 601 and 602, and other fringecomponents of the generated electric field 615 can extend in otherdirections. For example, the fringe components can extend from thetransmitter electrode or first electrode 601 away from the housingstructure 150 (not pictured in the example of FIG. 6) and terminate backat the receiver electrode or second electrode 602.

Information about the electric field 615, including information aboutchanges in the electric field 615 due to proximity of the body 550, canbe sensed or received by the second electrode 602. Signals sensed fromthe second electrode 602 can be processed using various circuitry andused to provide an analog or digital signal indicative of presence orabsence of the body 550.

For example, a field strength of the electric field 615 received by thesecond electrode 602 can be measured using a sigma-deltaanalog-to-digital converter circuit (ADC) 620 that is configured toconvert analog capacitance-indicating signals to digital signals. Theelectrical environment near the electrodes changes when an object, suchas the body 550, invades the electric field 615, including its fringecomponents. When the body 550 enters the field, a portion of theelectric field 615 is shunted to ground instead of being received andterminated at the second electrode 602 or passes through the body 550(e.g., instead of through air) before being received at the secondelectrode 602. This can result in a capacitance change that can bedetected by the foot presence sensor 310 and/or by the processor circuit320.

In an example, the second electrode 602 can receive electric fieldinformation substantially continuously, and the information can besampled continuously or periodically by the ADC 620. Information fromthe ADC 620 can be processed or updated according to an offset 621, andthen a digital output signal 622 can be provided. In an example, theoffset 621 is a capacitance offset that can be specified or programmed(e.g., internally to the processor circuit 320) or can be based onanother capacitor used for tracking environmental changes over time,temperature, and other variable characteristics of an environment.

In an example, the digital output signal 622 can include binaryinformation about a determined presence or absence of the body 550, suchas by comparing a measured capacitance value to a specified thresholdvalue. In an example, the digital output signal 622 includes qualitativeinformation about a measured capacitance, such as can be used (e.g., bythe processor circuit 320) to provide an indication of a likelihood thatthe body 550 is or is not present.

Periodically, or whenever the foot presence sensor 310 is not active(e.g., as determined using information from the motion sensor 324), acapacitance value can be measured and stored as a reference value,baseline value, or ambient value. When a foot or body approaches thefoot presence sensor 310 and the first and second electrodes 601 and602, the measured capacitance can decrease or increase, such as relativeto the stored reference value. In an example, one or more thresholdcapacitance levels can be stored, e.g., in on-chip registers with theprocessor circuit 320. When a measured capacitance value exceeds aspecified threshold, then the body 550 can be determined to be present(or absent) from footwear containing the foot presence sensor 310.

The foot presence sensor 310, and the electrodes 601 and 602 comprisinga portion of the foot presence sensor 310, can take multiple differentforms as illustrated in the several non-limiting examples that follow.In an example, the foot presence sensor 310 is configured to sense oruse information about a mutual capacitance among or between multipleelectrodes or plates.

In an example, the electrodes 601 and 602 are arranged in an electrodegrid. A capacitive sensor that uses the grid can include a variablecapacitor at each intersection of each row and each column of the grid.Optionally, the electrode grid includes electrodes arranged in one ormultiple rows or columns. A voltage signal can be applied to the rows orcolumns, and a body or foot near the surface of the sensor can influencea local electric field and, in turn, can reduce a mutual capacitanceeffect. In an example, a capacitance change at multiple points on thegrid can be measured to determine a body location, such as by measuringa voltage in each axis. In an example, mutual capacitance measuringtechniques can provide information from multiple locations around thegrid at the same time.

In an example, a mutual capacitance measurement uses an orthogonal gridof transmit and receive electrodes. In such a grid-based sensor system,measurements can be detected for each of multiple discrete X-Ycoordinate pairs. In an example, capacitance information from multiplecapacitors can be used to determine foot presence or foot orientation infootwear. In another example, capacitance information from one or morecapacitors can be acquired over time and analyzed to determine a footpresence or foot orientation. In an example, rate of change informationabout X and/or Y detection coordinates can be used to determine when orif a foot is properly or completely seated with respect to an insole infootwear.

In an example, a self-capacitance based foot presence sensor can havethe same X-Y grid as a mutual capacitance sensor, but the columns androws can operate independently. In a self-capacitance sensor, capacitiveloading of a body at each column or row can be detected independently.

FIG. 7 illustrates generally a schematic of a first capacitance-basedfoot presence sensor, according to an example embodiment. In the exampleof FIG. 7, a first capacitive sensor 700 includes multiple parallelcapacitive plates. The multiple plates can be arranged on or in thehousing structure 150, for example, positioned at or near an undersideof a foot when the footwear article including the first capacitivesensor 700 is worn. In an example, the capacitive foot presence sensor310 includes or uses the first capacitive sensor 700.

In the example of FIG. 7, four conductive capacitor plates areillustrated as 701-704. The plates can be made of a conductive materialsuch as a conductive foil. The foil can be flexible and can optionallybe embedded into a plastic of the housing structure 150 itself, or canbe independent of the housing structure 150. It is to be appreciatedthat any conductive material could be used, such as films, inks,deposited metals, or other materials. In the example of FIG. 7, theplates 701-704 are arranged in a common plane and are spaced apart fromeach other to form discrete conductive elements or electrodes.

A capacitance value of a capacitor is functionally related to adielectric constant of a material between two plates that form acapacitor. Within the first capacitive sensor 700, a capacitor can beformed between each pair of two or more of the capacitor plates 701-704.Accordingly, there are six effective capacitors formed by the six uniquecombination pairs of the capacitor plates 701-704 as designated in FIG.7 as capacitors A, B, C, D, E, and F. Optionally, two or more of theplates can be electrically coupled to form a single plate. That is, inan example, a capacitor can be formed using the first and secondcapacitor plates 701 and 702 electrically coupled to provide a firstconductor, and the third and fourth capacitor plates 703 and 704electrically coupled to provide a second conductor.

In an example, a capacitive effect between the first and secondcapacitor plates 701 and 702 is represented in FIG. 7 by a phantomcapacitor identified by letter A. The capacitive effect between thefirst and third capacitor plates 701 and 703 is represented by thephantom capacitor identified by letter B. The capacitive effect betweenthe second and fourth capacitor plates 702 and 704 is represented by thephantom capacitor identified by letter C, and so on. A person ofordinary skill in the art will appreciate that each phantom capacitor isrepresentative of an electrostatic field extending between therespective pair of capacitor plates. Hereinafter, for the purpose ofeasy identification, the capacitor formed by each pair of capacitiveplates is referred to by the letter (e.g., “A” “B”, etc.) used in FIG. 7to identify the phantom-drawn capacitors.

For each pair of capacitor plates in the example of FIG. 7, an effectivedielectric between the plates includes an airgap (or other material)disposed between the plates. For each pair of capacitor plates, anyportion of a body or foot that is proximal to the respective pair ofcapacitive plates can become part of, or can influence, an effectivedielectric for the given pair of capacitive plates. That is, a variabledielectric can be provided between each pair of capacitor platesaccording to a proximity of a body to the respective pair of plates. Forexample, the closer a body or foot is to a given pair of plates, thegreater the value of the effective dielectric may be. As the dielectricconstant value increases, the capacitance value increases. Such acapacitance value change can be received by the processor circuit 320and used to indicate whether a body is present at or near the firstcapacitive sensor 700.

In an example of the foot presence sensor 310 that includes the firstcapacitive sensor 700, a plurality of capacitive sensor drive/monitorcircuits can be coupled to the plates 701-704. For example, a separatedrive/monitor circuit can be associated with each pair of capacitorplates in the example of FIG. 7. In an example, drive/monitor circuitscan provide drive signals (e.g., time-varying electrical excitationsignals) to the capacitor plate pairs and, in response, can receivecapacitance-indicating values. Each drive/monitor circuit can beconfigured to measure a variable capacitance value of an associatedcapacitor (e.g., the capacitor “A” corresponding to the first and secondplates 701 and 702), and can be further configured to provide a signalindicative of the measured capacitance value. The drive/monitor circuitscan have any suitable structure for measuring the capacitance. In anexample, the two or more drive/monitor circuits can be used together,such as to provide an indication of a difference between capacitancevalues measured using different capacitors.

FIG. 8 illustrates generally a schematic of a second capacitance-basedfoot presence sensor, according to an example embodiment. The example ofFIG. 8 includes a second capacitive sensor 800 that includes first andsecond electrodes 801 and 802. The foot presence sensor 310 can includeor use the second capacitive sensor 800. In the example of FIG. 8, thefirst and second electrodes 801 and 802 are arranged along asubstantially planar surface, such as in a comb configuration. In anexample, a drive circuit, such as the processor circuit 320, can beconfigured to generate an excitation or stimulus signal to apply to thefirst and second electrodes 801 and 802. The same or different circuitcan be configured to sense a response signal indicative of a change incapacitance between the first and second electrodes 801 and 802. Thecapacitance can be influenced by the presence of a body or foot relativeto the electrodes. For example, the first and second electrodes 801 and802 can be arranged on or near a surface of the housing structure 150,such as proximal to a foot when the foot is present within footwear thatincludes the housing structure 150.

In an example, the second capacitive sensor 800 includes an etchedconductive layer, such as in an X-Y grid to form a pattern ofelectrodes. Additionally or alternatively, the electrodes of the secondcapacitive sensor 800 can be provided by etching multiple separate,parallel layers of conductive material, for example with perpendicularlines or tracks to form a grid. In this and other capacitive sensors, nodirect contact between a body or foot and a conductive layer orelectrode is needed. For example, the conductive layer or electrode canbe embedded in the housing structure 150, or can be coated with aprotective or insulating layer. Instead, the body or foot to be detectedcan interface with or influence an electric field characteristic nearthe electrodes, and changes in the electric field can be detected.

In an example, separate capacitance values can be measured for the firstelectrode 801 with respect to ground or to a reference, and for thesecond electrode 802 with respect to ground or to a reference. A signalfor use in foot presence detection can be based on a difference betweenthe separate capacitance values measured for the first and secondelectrodes 801 and 802. That is, the foot presence or foot detectionsignal can be based on a difference between discrete capacitance signalsthat are measured using the first and second electrodes 801 and 802.

FIGS. 9A and 9B illustrate generally examples of a third capacitivesensor 900, according to some examples. FIG. 9C illustrates generally anexample of a fourth capacitive sensor 902. FIG. 9A shows a schematic topview of the third capacitive sensor 900. FIG. 9B shows a perspectiveview of a sensor assembly 901 that includes the third capacitive sensor900. FIG. 9C shows a schematic top view of the fourth capacitive sensor902.

In the example of FIG. 9A, the third capacitive sensor 900 includes anelectrode region with a first electrode trace 911 and a second electrodetrace 912. The first and second electrode traces 911 and 912 areseparated by an insulator trace 913. In an example, the first and secondelectrode traces 911 and 912 can be copper, carbon, or silver, amongother conductive materials, and can be disposed on a substrate made fromFR4, flex, PET, or ITO, among other materials. The substrate and tracesof the third capacitive sensor 900 can include one or more flexibleportions.

The first and second electrode traces 911 and 912 can be distributedsubstantially across a surface area of a substrate of the thirdcapacitive sensor 900. The electrode traces can be positioned against anupper or top surface of the housing structure 150 when the thirdcapacitive sensor 900 is installed. In an example, one or both of thefirst and second electrode traces 911 and 912 can be about 2 mm wide.The insulator trace 913 can be about the same width. In an example, thetrace widths can be selected based on, among other things, a footwearsize or an insole type. For example, different trace widths can beselected for the first and second electrode traces 911 and 912 and/orfor the insulator trace 913 depending on, e.g., a distance between thetraces and the body to be sensed, an insole material, a gap filler,housing structure 150 material, or other materials used in the footwear,such as to maximize a signal-to-noise ratio of capacitance valuesmeasured using the third capacitive sensor 900.

The third capacitive sensor 900 can include a connector 915. Theconnector 915 can be coupled with a mating connector, such as coupled tothe PCA in the housing structure 150. The mating connector can includeone or more conductors to electrically couple the first and secondelectrode traces 911 and 912 with the processor circuit 320.

In an example, the third capacitive sensor 900 includes input signalconductors 920A and 920B. The input signal conductors 920A and 920B canbe configured to be coupled with one or more input devices, such as domebuttons or other switches, such as corresponding to the buttons 121 inthe example of FIG. 2A.

FIG. 9B illustrates the sensor assembly 901, including the thirdcapacitive sensor 900, the buttons 121A and 121B, and membrane seals124A and 124B. In an example, an adhesive couples correspondingconductive surfaces of the input signal conductors 920A and 920B withand the buttons 121A and 121B. The membrane seals 124A and 124B can beadhered over the buttons 121A and 121B, such as to protect the buttons121A and 121B from debris.

In the example of FIG. 9C, the fourth capacitive sensor 902 includes anelectrode region with a first electrode trace 921 and a second electrodetrace 922. The first and second electrode traces 921 and 922 areseparated by an insulator trace 923. The electrode traces can comprisevarious conductive materials, and the fourth capacitive sensor 902 caninclude one or more flexible portions. The four capacitive sensor 902can include a connector 925, and the connector 915 can be coupled with amating connector, such as coupled to the PCA in the housing structure150.

The present inventors have recognized that a problem to be solvedincludes obtaining a suitable sensitivity of or response from acapacitive foot presence sensor, for example, when all or a portion ofthe foot presence sensor is spaced apart from a foot or body to bedetected, such as by an air gap or other intervening material. Thepresent inventors have recognized that a solution can include usingmultiple electrodes of specified shapes, sizes, and orientations toenhance an orientation and relative strength of an electric field thatis produced when the electrodes are energized. That is, the presentinventors have identified an optimal electrode configuration for use incapacitive foot presence sensing.

In an example, multiple electrodes of the fourth capacitive sensor 902include the first and second electrode traces 921 and 922, and each ofthe first and second electrode traces 921 and 922 includes multiplediscrete fingers or traces that extend substantially parallel to oneanother. For example, the first and second electrode traces 921 and 922can include multiple interleaved conductive finger portions, as shown inFIG. 9C.

In an example, the second electrode trace 922 can include a shoreline orperimeter portion that extends substantially about the outer perimeteredge or surface portion of the fourth capacitive sensor 902, andsubstantially surrounds the first electrode trace 921. In the example ofFIG. 9C, the shoreline that includes the second electrode trace 922extends around substantially all of the top surface of the fourthcapacitive sensor 902 assembly, however, the shoreline can extend abouta lesser portion of the sensor in some other examples. The presentinventors have further recognized that an optimal electric field fordetecting foot presence is generated when most or all of the fingers offirst and second electrode traces 921 and 922 are arranged substantiallyparallel to one another, such as instead of including one or more tracesor finger portions that are non-parallel. For example, in contrast withthe fourth capacitive sensor 902, the third capacitive sensor 900 ofFIG. 9A includes non-parallel fingers, such as at an upper portion ofthe first electrode trace 911 that includes vertically extending fingerportions and at a lower portion of the first electrode trace 911 thatincludes horizontally extending finger portions. The relative thicknessof the first and second electrode traces 921 and 922 can be adjusted tofurther enhance sensitivity of the sensor. In an example, the secondelectrode trace 922 is three or more times thicker than the firstelectrode trace 921.

In an example, capacitance values measured by the foot presence sensor310, such as using one or more of the first, second, third, and fourthcapacitive sensors 700, 800, 900, and 902, can be provided to acontroller or processor circuit, such as the processor circuit 320 ofFIG. 3. In response to the measured capacitance, the processor circuit320 can actuate the drive mechanism 340, such as to adjust a footweartension about a foot. The adjusting operation can optionally beperformed at least in part by discrete, “hard-wired” components, can beperformed by a processor executing software, or can be performed be acombination of hard-wired components and software. In an example,actuating the drive mechanism 340 includes (1) monitoring signals fromthe foot presence sensor 310 using one or more drive/monitor circuits,such as using the processor circuit 320, (2) determining which, if any,of received capacitance signals indicate a capacitance value that meetsor exceeds a specified threshold value (e.g., stored in memory registersof the processor circuit 320 and/or in a memory circuit in datacommunication with the processor circuit 320), (3) characterizing alocation, size, orientation, or other characteristic of a body or footnear the foot presence sensor 310, such as based upon various specifiedthreshold values that are exceeded, and (4) permitting, enabling,adjusting, or suppressing actuation of the drive mechanism 340 dependingupon the characterization.

FIG. 10 illustrates a flowchart showing an example of a method 1000 thatincludes using foot presence information from a footwear sensor. Atoperation 1010, the example includes receiving foot presence informationfrom the foot presence sensor 310. The foot presence information caninclude binary information about whether or not a foot is present infootwear (see, e.g., the interrupt signals discussed in the examples ofFIGS. 12-14), or can include an indication of a likelihood that a footis present in a footwear article. The information can include anelectrical signal provided from the foot presence sensor 310 to theprocessor circuit 320. In an example, the foot presence informationincludes qualitative information about a location of a foot relative toone or more sensors in the footwear.

At operation 1020, the example includes determining whether a foot isfully seated in the footwear. If the sensor signal indicates that thefoot is fully seated, then the example can continue at operation 1030with actuating the drive mechanism 340. For example, when a foot isdetermined to be fully seated at operation 1020, such as based oninformation from the foot presence sensor 310, the drive mechanism 340can be engaged to tighten footwear laces via the spool 131, as describedabove. If the sensor signal indicates that the foot is not fully seated,then the example can continue at operation 1022 by delaying or idlingfor some specified interval (e.g., 1-2 seconds, or more). After thespecified delay elapses, the example can return to operation 1010, andthe processor circuit can re-sample information from the foot presencesensor 310 to determine again whether the foot is fully seated.

After the drive mechanism 340 is actuated at operation 1030, theprocessor circuit 320 can be configured to monitor foot locationinformation at operation 1040. For example, the processor circuit can beconfigured to periodically or intermittently monitor information fromthe foot presence sensor 310 about an absolute or relative position of afoot in the footwear. In an example, monitoring foot locationinformation at operation 1040 and receiving foot presence information atoperation 1010 can include receiving information from the same ordifferent foot presence sensor 310. For example, different electrodescan be used to monitor foot presence or position information atoperations 1010 and 1040.

At operation 1040, the example includes monitoring information from oneor more buttons associated with the footwear, such as the buttons 121.Based on information from the buttons 121, the drive mechanism 340 canbe instructed to disengage or loosen laces, such as when a user wishesto remove the footwear.

In an example, lace tension information can be additionally oralternatively monitored or used as feedback information for actuatingthe drive mechanism 340, or for tensioning laces. For example, lacetension information can be monitored by measuring a drive currentsupplied to the motor 341. The tension can be characterized at a pointof manufacture or can be preset or adjusted by a user, and can becorrelated to a monitored or measured drive current level.

At operation 1050, the example includes determining whether a footlocation has changed in the footwear. If no change in foot location isdetected by the foot presence sensor 310 and the processor circuit 320,then the example can continue with a delay at operation 1052. After aspecified delay interval at operation 1052, the example can return tooperation 1040 to re-sample information from the foot presence sensor310 to again determine whether a foot position has changed. The delay atoperation 1052 can be in the range of several milliseconds to severalseconds, and can optionally be specified by a user.

In an example, the delay at operation 1052 can be determinedautomatically by the processor circuit 320, such as in response todetermining a footwear use characteristic. For example, if the processorcircuit 320 determines that a wearer is engaged in strenuous activity(e.g., running, jumping, etc.), then the processor circuit 320 candecrease a delay duration provided at operation 1052. If the processorcircuit determines that the wearer is engaged in non-strenuous activity(e.g., walking or sitting), then the processor circuit can increase thedelay duration provided at operation 1052. By increasing a delayduration, battery life can be preserved by deferring sensor samplingevents and corresponding consumption of power by the processor circuit320 and/or by the foot presence sensor 310. In an example, if a locationchange is detected at operation 1050, then the example can continue byreturning to operation 1030, for example, to actuate the drive mechanism340 to tighten or loosen the footwear about the foot. In an example, theprocessor circuit 320 includes or incorporates a hysteretic controllerfor the drive mechanism 340 to help avoid unwanted lace spooling in theevent of, e.g., minor detected changes in foot position.

FIG. 11 illustrates a flowchart showing an example of a method 1100 ofusing foot presence information from a footwear sensor. The example ofFIG. 11 can, in an example, refer to operations of a state machine, suchas can be implemented using the processor circuit 320 and the footpresence sensor 310.

State 1110 can include a “Ship” state that represents a default orbaseline state for an active footwear article, the article including oneor more features that can be influenced by information from the footpresence sensor 310. In the Ship state 1110, various active componentsof the footwear can be switched off or deactivated to preserve thefootwear's battery life.

In response to a “Power Up” event 1115, the example can transition to a“Disabled” or inactive state 1120. The drive mechanism 340, or otherfeatures of the active footwear, can remain on standby in the Disabledstate 1120. Various inputs can be used as triggering events to exit theDisabled state 1120. For example, a user input from one of the buttons121 can be used to indicate a transition out of the Disabled state 1120.In an example, information from the motion sensor 324 can be used as awake-up signal. Information from the motion sensor 324 can includeinformation about movement of the footwear, such as can correspond to auser placing the shoes in a ready position, or a user beginning toinsert a foot into the footwear.

The state machine can remain in the Disabled state 1120 following thePower Up event 1115 until an Autolace enabled event 1123 is encounteredor received. The Autolace enabled event 1123 can be triggered manuallyby a user (e.g., using a user input or interface device to the drivemechanism 340), or can be triggered automatically in response to, e.g.,gesture information received from the motion sensor 324. Following theAutolace enabled event 1123, a Calibrate event 1125 can occur. TheCalibrate event 1125 can include setting a reference or baseline valuefor a capacitance of the foot presence sensor 310, such as to accountfor environmental effects on the sensor. The calibration can beperformed based on information sensed from the foot presence sensor 310itself or can be based on programmed or specified reference information.

Following the Autolace enabled event 1123, the state machine can enter aholding state 1130 to “Wait for foot presence signal”. At state 1130,the state machine can wait for an interrupt signal from the footpresence sensor 310 and/or from the motion sensor 324. Upon receipt ofthe interrupt signal, such as indicating a foot is present, orindicating a sufficient likelihood that a foot is present, an eventregister can indicate “Foot found” at event 1135.

The state machine can transition to or initiate various functions when aFoot found event 1135 occurs. For example, the footwear can beconfigured to tighten or adjust a tension characteristic using the drivemechanism 340 in response to the Foot found event 1135. In an example,the processor circuit 320 actuates the drive mechanism 340 to a adjustlace tension by an initial amount in response to the Foot found event1135, and the processor circuit 320 delays further tensioning thefootwear unless or until a further control gesture is detected or userinput is received. That is, the state machine can transition to a “Waitfor move” state 1140. In an example, the processor circuit 320 enablesthe drive mechanism 340 but does not actuate the drive mechanismfollowing the Foot found event 1135. At state 1140, the state machinecan hold or pause for additional sensed footwear motion informationbefore initiating any initial or further tension adjustment. Followingthe Wait for move state 1140, a Stomp/Walk/Stand event 1145 can bedetected and, in response, the processor circuit 320 can further adjusta tension characteristic for the footwear.

The Stomp Walk/Stand event 1145 can include various discrete, sensedinputs, such as from one or more sensors in the active footwear. Forexample, a Stomp event can include information from the motion sensor324 that indicates an affirmative acceleration (e.g., in a specified orgeneric direction) and an “up” or “upright” orientation. In an example,a Stomp event includes a “high knee” or kick type event where a userraises one knee substantially vertically and forward. An accelerationcharacteristic from the motion sensor 324 can be analyzed, such as todetermine whether the acceleration meets or exceeds a specifiedthreshold. For example, a slow knee-raise event may not trigger a Stompevent response, whereas a rapid or quick knee-raise event may trigger aStomp event response.

A Walk event can include information from the motion sensor 324 thatindicates an affirmative step pattern and an “up” or “upright”orientation. In an example, the motion sensor 324 and/or the processorcircuit 320 is configured to identify a step event, and the Walk eventcan be recognized when the step event is identified and when anaccelerometer (e.g., included with or separate from the motion sensor324) indicates that the footwear is upright.

A Stand event can include information from the motion sensor thatindicates an “up” or “upright” orientation, such as without furtherinformation about an acceleration or direction change of the footwearfrom the motion sensor. In an example, the Stand event can be discernedusing information about a change in a capacitance signal from thecapacitive foot presence sensor 310, such as further described below.That is, a capacitance signal from the foot presence sensor 310 caninclude signal variations that can indicate whether a user is standing,such as when the user's foot applies downward pressure on the footwear.

The specific examples of the Stomp/Walk Stand event 1145 are not to beconsidered limiting and various other gestures, time-based inputs, oruser-input controls can be provided to further control or influencebehavior of the footwear, such as after a foot is detected at the Footfound event 1135.

Following the Stomp Walk Stand event 1145, the state machine can includea “Wait for unlace” state 1150. The Wait for unlace state 1150 caninclude monitoring user inputs and/or gesture information (e.g., usingthe motion sensor 324) for instructions to relax, de-tension, or unlacethe footwear. In the Wait for unlace state 1150, a state manager such asthe processor circuit 320 can indicate that the lacing engine or drivemechanism 340 is unlaced and should return to the Wait for foot presencesignal state 1130. That is, in a first example, an Unlaced event 1155can occur (e.g., in response to a user input), the state machine cantransition the footwear to an unlaced state, and the state machine canreturn to the Wait for foot presence signal state 1130. In a secondexample, an Autolace disabled event 1153 can occur and transition thefootwear to the Disabled state 1120.

FIG. 12 illustrates generally a chart 1200 of first time-varyinginformation from a capacitive foot presence sensor. The example of FIG.12 includes a capacitance vs. time chart and a first time-varyingcapacitance signal 1201 plotted on the chart. In an example, the firsttime-varying capacitance signal 1201 can be obtained using the footpresence sensor 310 described herein. The first time-varying capacitancesignal 1201 can correspond to a measured capacitance, or an indicationof an influence of a body on an electric field, between multipleelectrodes in the foot presence sensor 310, as described above. In anexample, the first time-varying capacitance signal 1201 represents anabsolute or relative capacitance value, and in another example, thesignal represents a difference between multiple different capacitancesignals.

In an example, the first capacitance signal 1201 can be compared with aspecified first threshold capacitance value 1211. The foot presencesensor 310 can be configured to perform the comparison, or the processorcircuit 320 can be configured to receive capacitance information fromthe foot presence sensor 310 and perform the comparison. In the exampleof FIG. 12, the first threshold capacitance value 1211 is indicated tobe a constant non-zero value. When the first capacitance signal 1201meets or exceeds the first threshold capacitance value 1211, such as attime T₁, the foot presence sensor 310 and/or the processor circuit 320can provide a first interrupt signal INT₁. The first interrupt signalINT₁ can remain high as long as the capacitance value indicated by thefoot presence sensor 310 meets or exceeds the first thresholdcapacitance value 1211.

In an example, the first interrupt signal INT₁ can be used in theexample of FIG. 10, such as at operations 1010 or 1020. At operation1010, receiving foot presence information from the foot presence sensor310 can include receiving the first interrupt signal INT₁, such as atthe processor circuit 320. In an example, operation 1020 can includeusing interrupt signal information to determine whether a foot is, or islikely to be, fully seated in footwear. For example, the processorcircuit 320 can monitor a duration of the first interrupt signal INT₁ todetermine how long the foot presence sensor 310 provides a capacitancevalue that exceeds the first threshold capacitance value 1211. If theduration exceeds a specified reference duration, then the processorcircuit 320 can determine that a foot is, or is likely to be, fullyseated.

In an example, the first interrupt signal INT₁ can be used in theexample of FIG. 11, such as at state 1130 or event 1135. At state 1130,the state machine can be configured to wait for an interrupt signal,such as INT₁, from the processor circuit 320 or from the foot presencesensor 310. At event 1135, the state machine can receive the firstinterrupt signal INT₁ and, in response, one or more following states canbe initiated.

In an example, the first threshold capacitance value 1211 is adjustable.The threshold can change based on measured or detected changes in acapacitance baseline or reference, such as due to environment changes.In an example, the first threshold capacitance value 1211 can bespecified by a user. The user's specification of the threshold value caninfluence a sensitivity of the footwear. In an example, the firstthreshold capacitance value 1211 can be adjusted automatically inresponse to sensed environment or material changes in or around the footpresence sensor 310.

FIG. 13 illustrates generally a chart 1300 of second time-varyinginformation from a capacitive foot presence sensor. The example of FIG.13 shows how fluctuations of a second capacitance signal 1202 near thefirst threshold capacitance value 1211 can be handled or used todetermine more information about a foot presence or orientation infootwear.

In an example, the second capacitance signal 1202 is received from thefoot presence sensor 310, and the second capacitance signal 1202 iscompared with the first threshold capacitance value 1211. Otherthreshold values can similarly be used depending on, among other things,a user, a user preference, a footwear type, or an environment orenvironment characteristic. In the example of FIG. 13, the secondcapacitance signal 1202 can cross the first threshold capacitance value1211 at times T₂, T₃, and T₄. In an example, the multiple thresholdcrossings can be used to positively identify a foot presence by the footpresence sensor 310, such as by indicating a travel path for a foot asit enters the footwear. For example, the time interval bounded by thefirst and second threshold crossings at times T₂ and T₃ can indicate aduration when a foot's toes or phalanges are positioned at or nearelectrodes of the foot presence sensor 310. The interval between T₃ andT₄, when the sensed capacitance is less than the first thresholdcapacitance value 1211, can correspond to a time when the foot'smetatarsal joints or metatarsal bones travel over or near the electrodesof the foot presence sensor 310. The metatarsal joints and bones can bespaced away from the foot presence sensor 310 by a distance that isgreater than a distance of the phalanges to the foot presence sensor 310when the phalanges travel into the footwear, and therefore the resultingmeasured capacitance between T₃ and T₄ can be less. At time T₄, the heelor talus of the foot can slide into position and the arch can becomeseated over electrodes of the foot presence sensor 310, thereby bringinga sensed capacitance back up and exceeding the first thresholdcapacitance value 1211. Accordingly, the foot presence sensor 310 or theprocessor circuit 320 can be configured to render a second interruptsignal INT₂ between times T₂ and T₃, and to render a third interruptsignal INT₃ following time T₄.

In an example, the processor circuit 320 can be configured to positivelyidentify a foot presence based on a sequence of interrupt signals. Forexample, the processor circuit 320 can use information about receivedinterrupt signals and about one or more intervals or durations betweenthe received interrupt signals. For example, the processor circuit canbe configured to look for a pair of interrupt signals separated by aspecified duration to provide a positive indication of a foot presence.In FIG. 13, for example, a duration between T₃ and T₄ can be used toprovide an indication of a foot presence, such as with some adjustableor specified margin of error. In an example, the processor circuit 320can receive interrupt signals as data and process the data together withother user input signals, for example as part of a gesture-based userinput. In an example, information about a presence or absence of aninterrupt signal can be used to validate or dismiss one or more othersignals. For example, an accelerometer signal can be validated andprocessed by the processor circuit 320 when an interrupt signal is orwas recently received, or the accelerometer signal can be dismissed bythe processor circuit 320 when an interrupt signal corresponding to thefoot presence sensor is absent.

The examples of FIG. 12 and FIG. 13 show embodiments wherein measuredcapacitance values from the foot presence sensor 310 are reliablyconstant or reproducible over time, including in the presence of changesin environmental conditions. In many footwear use cases, however,ambient capacitance changes in embedded electronics can occur constantlyor unpredictably, such as due to changes in temperature, humidity, orother environmental factors. Significant changes in ambient capacitancecan adversely affect activation of the foot presence sensor 310, such asby changing a baseline or reference capacitance characteristic of thesensor.

FIG. 14 illustrates generally a chart 1400 of third time-varyinginformation from a capacitive foot presence sensor. The example of FIG.14 shows how reference capacitance changes, such as due to changes invarious ambient conditions, changes in use scenarios, or changes due towear and tear or degradation of footwear components, can be accountedfor. The example includes a third capacitance signal 1203 plotted on thechart 1400 with a second threshold capacitance 1212 and a time-varyingreference capacitance 1213. In the example of FIG. 14, the time-varyingreference capacitance 1213 increases over time. In other examples, areference capacitance can decrease over time, or can fluctuate, such asover the course of a footwear usage event (e.g., over the course of oneday, one game played, one user's settings or preferences, etc.). In anexample, a reference capacitance can change over a life cycle of variouscomponents of the footwear itself, such as an insole, outsole, sockliner, orthotic insert, or other component of the footwear.

In an example, the third capacitance signal 1203 is received from thefoot presence sensor 310, and the third capacitance signal 1203 iscompared with the second threshold capacitance 1212, such as usingprocessing circuitry on the foot presence sensor 310 or using theprocessor circuit 320. In an example that does not consider or use thetime-varying reference capacitance 1213, threshold crossings for thethird capacitance signal 1203 can be observed at times T₅, T₆, and T₈.The second threshold capacitance 1212 can be adjusted, however, such asin real-time with the sensed information from the foot presence sensor310. Adjustments to the second threshold capacitance 1212 can be basedon the time-varying reference capacitance 1213.

In an example, the second threshold capacitance 1212 is adjustedcontinuously and by amounts that correspond to changes in thetime-varying reference capacitance 1213. In an alternative example, thesecond threshold capacitance 1212 is adjusted in stepped increments,such as in response to specified threshold change amounts of thetime-varying reference capacitance 1213. The stepped-adjustmenttechnique is illustrated in FIG. 14 by the stepped increase in thesecond threshold capacitance 1212 over the interval shown. For example,the second threshold capacitance 1212 is increased at times T₇ and T₁₀in response to specified threshold increases in capacitance, ΔC, in thetime-varying reference capacitance 1213. In the example of FIG. 14, thethird capacitance signal 1203 crosses the reference-compensated secondthreshold capacitance 1212 at times T₅, T₆, and T₉. Thus differentinterrupt signals or interrupt signal timings can be provided dependingon whether the threshold is reference-compensated. For example, a fourthinterrupt signal INT₄ can be generated and provided between times T₅ andT₆. If the second threshold capacitance 1212 is used without referencecompensation, then a fifth interrupt signal INT₅ can be generated andprovided at time T₈. However, if the reference-compensated secondthreshold capacitance 1212 is used, then the fifth interrupt signal INT₅is generated and provided at time T₉ as illustrated when the thirdcapacitance signal 1203 crosses the compensated second thresholdcapacitance 1212.

Logic circuits can be used to monitor and update threshold capacitancevalues. Such logic circuits can be incorporated with the foot presencesensor 310 or with the processor circuit 320. Updated threshold levelscan be provided automatically and stored in the on-chip RAM. In anexample, no input or confirmation from a user is needed to perform athreshold update.

FIG. 15 illustrates generally a chart 1500 of fourth time-varyinginformation from a capacitive foot presence sensor. The example of FIG.15 shows how reference capacitance changes, such as due to changes invarious ambient conditions, changes in use scenarios, or changes due towear and tear or degradation of footwear components, can be accountedfor. The example includes a fourth capacitance signal 1204 plotted onthe chart 1500 with an adaptive threshold capacitance 1214. The fourthcapacitance signal 1204 can be provided by the foot presence sensor 310.The adaptive threshold capacitance 1214 can be used to help compensatefor environment or use-case-related changes in capacitance measured bythe foot presence sensor 310.

In an example, the foot presence sensor 310 or processor circuit 320 isconfigured to monitor the fourth capacitance signal 1204 for signalmagnitude changes, such as for changes greater than a specifiedthreshold magnitude amount. That is, when the fourth capacitance signal1204 includes a magnitude change that meets or exceeds a specifiedthreshold capacitance magnitude, ΔC, then the foot presence sensor 310or processor circuit 320 can provide an interrupt signal.

In an example, sensed or measured capacitance values of the fourthcapacitance signal 1204 are compared with a reference capacitance orbaseline, and that reference or baseline can be updated at specified ortime-varying intervals. In the example of FIG. 15, a reference updateoccurs periodically at times T₁₁, T₁₂, T₁₃, etc., as shown. Otherintervals, or updates in response to other triggering events, canadditionally or alternatively be used.

In the example of FIG. 15, an initial reference capacitance can be 0, orcan be represented by the x-axis. A sixth interrupt signal INT₆ can beprovided at time T₁₁ after the fourth capacitance signal 1204 increasesby greater than the specified threshold capacitance magnitude ΔCrelative to a previously specified reference. In the example of FIG. 15,interrupts can be provided at periodic intervals, however, in otherexamples an interrupt can be provided contemporaneously with identifyingthe threshold change in capacitance.

Following the identified threshold change, such as at time T₁₁,reference or baseline capacitance can be updated to a first capacitancereference C₁. Following time T₁₁, the foot presence sensor 310 orprocessor circuit 320 can be configured to monitor the fourthcapacitance signal 1204 for a subsequent change by at least ΔC in thesignal, that is, to look for a capacitance value of C₁+ΔC or C₁−ΔC.

In an example that includes identifying a capacitance increase at afirst time, the interrupt signal status can be changed in response toidentifying a capacitance decrease at a subsequent time. However, if afurther capacitance increase is identified at the subsequent time, thenthe reference capacitance can be updated and subsequent comparisons canbe made based on the updated reference capacitance. This scenario isillustrated in FIG. 15. For example, at time T₁₂, a capacitance increasein the fourth capacitance signal 1204 is detected, and the reference canbe updated to a second capacitance reference C₂. Since the first andsubsequent second capacitance changes represent increases, the status ofthe sixth interrupt signal INT₆ can be unchanged. At time T₁₃, acapacitance decrease in the fourth capacitance signal 1204 is detected,and the reference can be updated to a third capacitance reference C₃.Since the capacitance change at time T₁₃ is a decrease that is greaterthan the specified threshold capacitance magnitude ΔC, the status of thesixth interrupt signal INT₆ can be changed (e.g., from an interruptasserted state to an unasserted state).

In an example, the first detected change at time T₁₁ and correspondinginterrupt signal INT₆ represents a foot that is sensed by the footpresence sensor 310 and determined to be present in footwear. Subsequentincreases in the reference capacitance represent changes to a baselinecapacitance measured by the foot presence sensor 310, such as due toenvironment changes at or near the sensor. The detected change at timeT₁₃ can represent a foot being removed from the footwear and being nolonger sensed proximal to the foot presence sensor 310. A subsequentcapacitance change (e.g., at time T₁₆) can represent the foot beingre-inserted into the footwear.

FIG. 16 illustrates generally a chart 1600 of time-varying informationfrom a capacitive foot presence sensor and a signal morphology limit,according to an example embodiment. The example includes fifth and sixthcapacitance signals 1205 and 1206 plotted on the chart 1600. The chart1600 further includes a morphology limit 1601. The morphology limit 1601can be compared to sampled segments of a capacitance signal from thefoot presence sensor 310. The comparison can be performed using the footpresence sensor 310 or processor circuit 320 to determine whether aparticular sampled segment conforms to the morphology limit 1601. In theexample of FIG. 16, the morphology limit defines a lower limit that, ifexceeded, indicates that the capacitance signal segment does notrepresent, or is unlikely to represent, a foot presence proximal to thefoot presence sensor 310.

The illustrated sampled portion of the fifth capacitance signal 1205conforms to the morphology limit 1601. In the example of FIG. 16, themorphology limit 1601 defines a morphology that includes a capacitancesignal magnitude change, or dip, dwell, and recovery. Followingidentification that the fifth capacitance signal 1205 conforms to all ora portion of the morphology limit 1601, an interrupt signal can beprovided to indicate a foot presence or successful detection.

The illustrated sampled portion of the sixth capacitance signal 1206does not conform to the morphology limit 1601. For example, the steepdecrease and long dwell time of the sixth capacitance signal 1206 fallsoutside of the bounds defined by the morphology limit 1601, andtherefore an interrupt signal can be withheld, such as to indicate thata foot is not detected by the foot presence sensor 310.

The morphology limit 1601 can be fixed or variable. For example, themorphology limit can be adjusted based on information about a referencecapacitance, environment, footwear use case, user, sensitivitypreference, or other information. For example, the morphology limit 1601can be different depending on a type of footwear used. That is, abasketball shoe can have a different morphology limit 1601 than arunning shoe, at least in part because of the different geometry ormaterials of the shoes or an amount of time that a user is expected totake to put on or take off a particular footwear article. In an example,the morphology limit 1601 can be programmed by a user, such as tocorrespond to a user's unique footwear donning or doffing preferences orprocedures.

As explained above, the foot presence sensor 310 can have an associatedfixed or variable baseline or reference capacitance value. The referencecapacitance value can be a function of an electrode surface area, or ofan electrode placement relative to other footwear components, or of afootwear orientation, or of an environment in which the sensor orfootwear itself it used. That is, a sensor can have some associatedcapacitance value without a foot present in the footwear, and that valuecan be a function of a dielectric effect of one or more materials orenvironmental factors at or near the sensor. In an example, an orthoticinsert (e.g., insole) in footwear can change a dielectric characteristicof the footwear at or near a capacitive sensor. The processor circuit320 can optionally be configured to calibrate the foot presence sensor310 when a baseline or reference characteristic changes, such as when aninsole is changed. In an example, the processor circuit 320 can beconfigured to automatically detect baseline or reference capacitancechanges, or can be configured to update a baseline or referencecapacitance in response to a user input or command.

FIG. 17 illustrates generally an example 1700 of a diagram of acapacitance-based foot presence sensor in a midsole of a footweararticle and located under a dielectric stack. The example 1700 includesthe housing structure 150, such as can include or use a lacing engine ordrive mechanism 340 that is actuated at least in part based oninformation from a capacitive foot presence sensor 1701. The capacitivefoot presence sensor 1701 can be configured to provide a capacitance orcapacitance-indicating signal based on a presence or absence of the body550 proximal to the sensor.

One or more materials can be provided between the body 550 and thecapacitive foot presence sensor 1701, and the one or more materials caninfluence the sensitivity of the sensor, or can influence asignal-to-noise ratio of a signal from the sensor. In an example, theone or more materials form a dielectric stack. The one or more materialscan include, among other things, a sock 1751, an airgap such as due toan arch height of the body 550 at or near the sensor, a sock liner 1750,a fastener 1730 such as Velcro, or a dielectric filler 1720. In anexample, when the capacitive foot presence sensor 1701 is providedinside of the housing structure 150 the top wall of the housingstructure 150 itself is a portion of the dielectric stack. In anexample, an orthotic insert can be a portion of the dielectric stack.

The present inventors have recognized that providing a dielectric stackwith a high relative permittivity, or a high k-value, can enhance theinput sensitivity of the capacitive foot presence sensor 1701. Varioushigh k-value materials were tested and evaluated for effectiveness andsuitability in footwear. In an example, the dielectric filler 1720 caninclude a neoprene member. The neoprene member can be specified to havea hardness or durometer characteristic that is comfortable to useunderfoot in footwear and that provides a sufficient dielectric effectto increase the sensitivity of the capacitive foot presence sensor 1701,such as relative to having an airgap or other low k-value material inits place. In an example, the neoprene member includes a closed-cellfoam material with about a 30 shore A hardness value.

FIG. 18 illustrates generally an example that includes a chart 1800showing an effect of the dielectric filler 1720 on acapacitance-indicating signal from the capacitive foot presence sensor1701. In the chart 1800, the x axis indicates a number of digitalsamples and corresponds to time elapsed, and the y axis indicates arelative measure of capacitance detected by the capacitive foot presencesensor 1701. The chart 1800 includes a time-aligned overlay of acapacitance-indicating first signal 1801 corresponding to a first typeof the dielectric filler 1720 material and a capacitance-indicatingsecond signal 1802 corresponding to a different second type of thedielectric filter 1720.

In the example, the first signal 1801 corresponds to footwear with afirst dielectric member provided as the dielectric filler 1720. Thefirst dielectric member can include, for example, a polyurethane foamhaving a first dielectric k-value. The chart 1800 shows multipleinstances of the body 550 being inserted into and then removed from anarticle of footwear that includes the first dielectric member and thefoot presence sensor 1701. For example, a first portion 1820 of thefirst signal 1801 indicates a reference or baseline capacitance measuredby the capacitive foot presence sensor 1701. In the example of FIG. 18,the reference or baseline is normalized to a value of zero. Thereference or baseline condition can correspond to no foot present in thefootwear. That is, the first portion 1820 of the first signal 1801indicates that a foot is absent from the footwear. At a timecorresponding to approximately sample 600, the body 550 can be insertedinto the footwear and can be situated at or near the capacitive footpresence sensor 1701 and the first dielectric member. Followinginsertion, a magnitude of the first signal 1801 changes, such as by afirst amount 1811, and indicates that a foot (or other body) is presentin the footwear. In the example of FIG. 18, the body 550 is present inthe footwear for a duration corresponding to a second portion 1821 ofthe first signal 1801, such as corresponding to approximately samples600 through 1400. At a time corresponding to approximately sample 1400,the body 550 can be removed from the footwear. When the body 550 isremoved, the first signal 1801 can return to its reference or baselinevalue.

In the example of FIG. 18, the second signal 1802 corresponds tofootwear with a second dielectric member provided as the dielectricfiller 1720. The second dielectric member can include, for example, aneoprene foam having a second dielectric k-value that exceeds the firstdielectric k-value of the first dielectric member discussed above. Thechart 1800 shows multiple instances of the body 550 being inserted intoand then removed from an article of footwear that includes the seconddielectric member and the foot presence sensor 1701. The first portion1820 of the second signal 1802 indicates a reference or baselinecapacitance measured by the capacitive foot presence sensor 1701 and, inthe example of FIG. 18, the first portion 1820 of the second signal 1802indicates that a foot is absent from the footwear. At a timecorresponding to approximately sample 600, the body 550 can be insertedinto the footwear and can be situated at or near the capacitive footpresence sensor 1701 and the second dielectric member. Followinginsertion, a magnitude of the second signal 1802 changes, such as by asecond amount 1812, and indicates that a foot (or other body) is presentin the footwear. In the example, the second amount 1812 exceeds thefirst amount 1811. The difference in magnitude change is attributed tothe type of material used for the dielectric filler 1720. That is, amagnitude of the capacitance-indicating first and second signals 1801and 1802 can be different when a different dielectric stack is used.When the dielectric stack includes a high k-value dielectric filler1720, then the difference in magnitude, or difference from baseline, isgreater than when a dielectric stack includes a low k-value dielectricfilter 1720.

In an example, an orthotic insert comprises a portion of a dielectricstack in footwear. The present inventors performed a variety of tests toevaluate an effect of various orthotic inserts on capacitive footsensing techniques. Full and partial length orthotic insoles weretested. The addition of a regular (partial length) orthotic to thefootwear increased an overall dielectric effect of the stack anddecreased an electric field sensitivity to the presence of a foot. Asensed signal amplitude (e.g., corresponding to a sensed change incapacitance) also decreased in the presence of the orthotic. An RMSamplitude of a noise floor, however, was similar with or without theorthotic. The response under loading and unloading conditions was alsosimilar.

Based on results of the orthotics tests, using capacitive sensing fordetection of foot presence with regular or full-length orthotics isfeasible with respect to signal to noise resolution. Using partial orfull length orthotics, a SNR exceeding a desired minimum of about 6 dBcan be used to resolve foot presence, and can be used under both lightduty and high duty loading conditions. In an example, the foot presencesensor 310 can include or use a capacitance offset range to compensatefor added dielectric effects of orthotics.

Variations in an air gap between a full-length orthotic and electrodesof the foot presence sensor 310 can correspond to measurable variationsin SNR as a function of an applied load. For example, as demonstrated inthe example of FIG. 18, when a high k-value dielectric material isprovided at or near a capacitive foot presence sensor, then the SNR canbe improved over examples that include or use a low k-value dielectricmaterial.

Various foot zones were found to behave similarly under low loadingconditions, such as showing no significant deformation of the gapdistance under the orthotic. Under high loading conditions, however,such as when a user is standing, an arch region of an orthotic can becompressed and an air gap can be substantially minimized or eliminated.Thus under sensing conditions, measured electric fields in the presenceof an orthotic can be similar in magnitude to electric fields measuredusing a production or OEM insole. In an example of an orthotic or OEMproduction insole that creates an airgap between the foot presencesensor 310 and a body to be detected, various materials can be providedor added to compensate for or fill in the airgap. For example, agap-filling foam such as neoprene can be provided at an underside of afull-length orthotic.

In an example, including an orthotic in an insole increases an overalldielectric thickness of a dielectric stack, decreasing the electricfield sensitivity to the presence of the foot. The signal amplitudedecreased with the orthotic. An RMS amplitude of a noise characteristicwas similar with or without the orthotic. It was also determined thatthe dielectric member that occupies a volume between a sense electrodeof a capacitive sensor and the lower surface of the orthotic can have alarge influence on the sensitivity of the capacitive sensor. Apolyurethane foam, for example having a k-value of 1.28, can have about70% less signal amplitude than that measured when using a neoprene foamwith a dielectric constant or k-value of about 5.6. With noise amplitudebeing equal, this equates to an SNR difference of about 4.6 dB.

Using capacitive sensing for detection of foot presence with carbonfiber orthotics is thus feasible with respect to signal to noise. TheSNR exceeds the minimum of 6 dB required to resolve foot presence wasmeasured.

FIG. 19 illustrates generally an example of a chart 1900 that shows aportion of a capacitance-indicating third signal 1803 from acapacitance-based foot presence sensor in footwear. In the chart 1900,the x axis indicates a number of digital samples and corresponds to timeelapsed, and the y axis indicates a relative measure of capacitancedetected by the capacitive foot presence sensor 1701. Information fromthe third signal 1803 can be used to determine whether a user isapplying a downward force on the footwear, such as can be used todiscern whether the user is sitting or standing, or to determine a stepcount, or to determine a user gait characteristic, among other things.

At an initial time, such as corresponding to sample “0” on the x axis,the third signal 1803 can have a reference or baseline value of about 0on the relative capacitance scale. At 1901, or at about sample 175 onthe x axis, the third signal 1803 includes a footwear donning eventcorresponding to, e.g., the body 550 being inserted into the footwear.The third signal 1803 includes a footwear doffing event at 1910, or atabout sample 10000, after which the third signal 1803 returns to thebaseline value.

The example of FIG. 19 further includes a threshold 1920. The threshold1920 can correspond to a relative capacitance value that indicates thebody 550 is present in the footwear. For example, when a foot or thebody 550 is present in the footwear, the relative capacitance indicatedby the third signal 1803 exceeds the threshold 1920, and when the footor body 550 is absent from the footwear, the relative capacitance canfall below the threshold 1920. Various methods or techniques can be usedto dynamically adjust the threshold 1920, such as further describedherein, such as to account for environmental changes or footwearmaterial changes.

Between the footwear donning and doffing events at 1901 and 1910,respectively, such as corresponding to an interval between samples 175and 1000, the wearer of the footwear article can transition multipletimes between sitting and standing positions. Transitions betweensitting and standing can correspond to fluctuations in the third signal1803 for example due to compression and relaxation of footwear materialsthat form a dielectric stack over a capacitive sensor that provides thethird signal 1803. That is, when a user stands and exerts a downwardforce on the dielectric stack, one or more materials in the dielectricstack can compress and the user's foot can move closer to the capacitivesensor, thereby changing a relative capacitance measured using thesensor. When a user sits and the downward force on the dielectric stackis reduced, then the dielectric stack materials can relax or extend, andthe user's foot can move away from the capacitive sensor.

The donning event 1901 includes a turbulent portion of the third signal1803. That is, instead of showing a smooth or gentle transition, thethird signal 1803 fluctuates rapidly and erratically as the user seatshis or her foot into position within the footwear. In an example, thedonning event 1901 includes lacing, such as automatic or manual lacing,which can correspond to a user exerting various forces on the footwearmaterials, including on the dielectric stack, and the user adjusting thefootwear's tension about the user's foot. In the example of FIG. 19,following the donning event at 1901, a user can be seated for a firstduration 1931, such as corresponding to samples 200 through 275. For thefirst duration 1931, the third signal 1803 can have an average value ofabout 220 relative capacitance units.

Following the first duration 1931, the user can stand, causing thematerial(s) of the dielectric stack to compress and thereby permittingthe user's foot to approach the capacitive sensor under the stack. Whenthe user is fully standing and compressing the dielectric stack, thethird signal 1803 can have an average value of about 120 relativecapacitance units for a second duration 1932. That is, a magnitude ofthe third signal 1803 can change by a first magnitude change amount 1951as the user transitions from sitting to standing, or as the usertransitions from exerting minimal force on the dielectric stack toexerting a maximum force on the dielectric stack, and thereby changing adielectric characteristic of the dielectric stack itself. In an example,the first magnitude change amount 1951 can correspond to a magnitude ofthe force exerted on the dielectric stack. That is, the first magnitudechange amount 1951 can be used to determine, among other things, auser's weight or whether the user is running or walking, for examplebecause the user is expected to exert a greater force on the dielectricstack when running as compared to walking.

In the example of FIG. 19, at about sample 375, the third signal 1803returns to a value of about 220 relative capacitance units when the userreturns to a seated posture. The user sits for a third duration 1933before the next relative capacitance change.

A dashed-line portion of the third signal 1803 (following about sample500 in the example of FIG. 19) indicates a time passage and a change inscale of the x axis. In an example, the samples 0 through 500 correspondto a time when footwear incorporating the capacitive sensor is new, orwhen a new dielectric stack is used with the footwear. The samplesfollowing about sample 9,800 can correspond to a time when the footwearis older or partially worn out, or when a portion of the dielectricstack is compressed and fails to recoil or expand under relaxed ornon-use conditions.

In the example of FIG. 19, the third signal 1803 indicates several usertransitions between sitting and standing postures. In the example, afourth duration 1934 and a sixth duration 1936 correspond to a sittingposture with minimal force or pressure applied to a dielectric stack inthe footwear. A fifth duration 1935 corresponds to a standing posturewith elevated force applied on the dielectric stack. In the example, thefourth and sixth durations 1934 and 1936 can correspond to an averagevalue of about 240 relative capacitance units. That is, the average ofthe fourth and sixth durations 1934 and 1936 can exceed the average ofthe first and third durations 1931 and 1933, which was about 220 units.In an example, the difference between the average values can beattributed to wear and tear of one or more portions of the dielectricstack or other footwear materials that change over time with use of thefootwear. In the example, the fifth duration 1935 can correspond to anaverage value of about 150 relative capacitance units, which exceeds theaverage value of about 120 units for the third duration 1933.Furthermore, the difference between sitting and standing postures, thatis between force applied or not applied to the dielectric stack, candiffer for the case of the new footwear and the used footwear. The firstmagnitude change amount 1951 indicates about a 200 unit change inrelative capacitance for new footwear between standing and seatedpostures, and a second magnitude change amount 1952 indicates about a150 unit change in relative capacitance for older or used footwearbetween standing and seated postures. In the example of FIG. 19, thefourth through sixth durations 1934-1936 further indicate a relativelynoisy signal as compared to the first through third durations 1931-1933,which can additionally be attributed to wear and tear of footwear orsensor components.

FIG. 19 thus illustrates that information from the third signal 1803 canbe used to indicate, among other things, a footwear lifecycle status orfootwear usage characteristic. The information can be used, for example,to help prevent user injury by reporting to or warning a user that oneor more footwear components are worn or exhausted, and may no longer beavailable to provide optimal or sufficient cushioning or foot retention.

In an example, information from a capacitive foot sensor can be used toderive or determine step frequency information, which can in turn beused as a step counter or pedometer, such as when a user's stride isknown or determinable. Referring again to FIG. 19, fluctuations in thethird signal 1803 can correspond to different step events. For example,the second duration 1932 can correspond to an interval that includes afirst portion of a user step, such as when a user's first foot is on theground and the user's body weight applies a force on the user'sfootwear, and the footwear includes a capacitance-based foot presencesensor that provides the third signal 1803. Following the secondduration 1932, the user can shift his or her weight from the user'sfirst foot to his or her second foot. As a result, pressure or forceapplied by the user to the footwear can be reduced, and a correspondingchange in the third signal 1803 can be observed. For example, amagnitude of the third signal 1803 can increase, such as by the firstmagnitude change amount 1951. When the user steps again and returns tothe first foot, then the magnitude of the third signal 1803 candecrease, such as by the same or similar first magnitude change amount1951. In an example, the magnitude change can depend on, or can berelated to, a force applied by the user on the footwear, which can inturn correspond to how quickly the user is walking or running. Forexample, a greater magnitude change amount can correspond to a runningpace, while a lesser change amount can correspond to a walking pace.

In an example, a duration, interval, or sample count of a specifiedportion of the third signal 1803 can be used to determine a stepinterval or step count. For example, the first duration 1931 can have asample count of about 75 samples, and the second duration 1932 can havea sample count of about 50 samples. If the first and duration 1931corresponds to a first portion of a user's walking or stepping cyclewhen a first foot is off the ground, and the second duration 1932corresponds to a later second portion of the user's walking or steppingcycle when the first foot is on the ground, then the user can have astep interval of about 125 samples. Depending on the sample rate, thestep interval can be correlated with a walking or running pace, such asusing the processor circuit 320 to process the sample count information.

In an example, a duration, interval, or sample count between signalmagnitude changes in the third signal 1803 can be used to determine astep interval or step count. Magnitude changes, such as greater than aspecified threshold magnitude change amount, can be identified by theprocessor circuit 320, and then the processor circuit 320 can calculateor identify interval lengths between the identified magnitude changes.For example, an onset of the second duration 1932 can be identified bythe processor circuit 320 to be at about sample 325, such ascorresponding to a magnitude change observed in the third signal 1803that is greater than a specified threshold change. An end of the secondduration 1932 can be identified by the processor circuit 320 to be atabout sample 375, such as corresponding to a subsequent magnitude changeobserved in the third signal 1803 and is greater than the specifiedthreshold change. The processor circuit 320 can calculate a differencebetween the sample counts and determine that the second. duration 1932is about 50 samples in duration. The processor circuit 320 can similarlydetermine a duration or sample length for any one or more segments ofthe third signal 1803. The processor circuit 320 can then determine astep interval, and a step interval can be used to determine a distancetraveled or a rate at which the user is moving. In an example,information about a user's stride length can be used together with thestep interval information to determine the distance traveled.

In an example, a user's stride length is not specified or known. Theuser's stride length can optionally be determined using information fromone or more other sensors, such as an accelerometer or position sensor(e.g., a GPS sensor) in coordination with the foot sensor information.For example, information from a position sensor can indicate a totaldistance traveled by a user over a specified duration. The processorcircuit 320, or other processor appurtenant to the footwear, can receivethe third signal 1803 and correlate a number of signal magnitude changeevents with steps and distance traveled to determine an average userstep or stride length. For example, if a user travels 100 meters in 30seconds, and a capacitance-indicating signal from a foot presence sensorindicates 100 signal magnitude change events within the same 30 secondinterval, then the processor circuit 320 or other processor candetermine the user's stride is about 100 meters/100 magnitude changeevents=1 meter per magnitude change event.

In an example, information from the third signal 1803 can be used todetermine a user gait characteristic, or a change in a user's gait. Theprocessor circuit 320 can, for example, be configured to monitor thecapacitance-indicating signal over time, such as to identify changes inthe signal. For example, the processor circuit 320 can monitor a first(or other) duration or first step event after a detected donning event.Generally, users can be expected to begin walking or running in asimilar manner, such as using a similar gait, each time the user donsthe footwear. If the processor circuit 320 detects a deviation from anestablished baseline or average signal characteristic following footweardonning, then the user can be alerted. Similarly, the processor circuit320 can be configured to detect usage characteristics or deviations thatcan be associated with user fatigue, which can in turn lead to injury.For example, a deviation from an established baseline or referencesignal characteristic can indicate a foot or ankle has rotated or slidwithin the footwear, such as because a foot position change cancorrespondingly change a dielectric characteristic at or above acapacitance-based foot presence sensor. In an example that includes anautomatic lacing engine, information about the foot position change canbe used to automatically tighten the footwear about the user's foot tohelp prevent injury to the user.

The following aspects provide a non-limiting overview of the footwearand capacitive sensors discussed herein.

Aspect 1 can include or use subject matter (such as an apparatus, asystem, a device, a method, a means for performing acts, or a devicereadable medium including instructions that, when performed by thedevice, can cause the device to perform acts), such as can include oruse a foot presence sensor system for an active footwear article, thesensor system comprising a controller circuit provided in the articleand configured to trigger one or more automated functions of the articlebased on a foot presence indication, and a capacitive sensor configuredto provide the foot presence indication, wherein the capacitive sensorincludes at least two spaced apart electrodes, and wherein theelectrodes are substantially parallel with an upper surface of an insoleof the article.

Aspect 2 can include or use, or can optionally be combined with thesubject matter of Aspect 1, to optionally include or use a sensorhousing configured to be disposed at or in one of an insole of thearticle and an outsole of the article, wherein the controller circuitand the capacitive sensor are disposed inside of the sensor housing.

Aspect 3 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 or 2 to optionallyinclude or use a device housing configured to be disposed at or in oneof an insole of the article and an outsole of the article, wherein thecontroller circuit is disposed inside of the device housing and thecapacitive sensor is disposed between an upper surface of the devicehousing and the insole of the article.

Aspect 4 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 through 3 tooptionally include or use the at least two electrodes disposed on acommon flexible substrate.

Aspect 5 can include or use, or can optionally be combined with thesubject matter of Aspect 4, to optionally include or use one of theelectrodes extending substantially around at least a portion of theother one of the electrodes.

Aspect 6 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 through 5 tooptionally include or use the at least two electrodes being first andsecond comb-shaped electrodes, each comb-shaped electrode havingmultiple spaced apart extension members.

Aspect 7 can include or use, or can optionally be combined with thesubject matter of Aspect 6, to optionally include or use the extensionmembers of the first and second comb-shaped electrodes are interleaved.

Aspect 8 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 through 7 tooptionally include or use the capacitive sensor or the controllercircuit includes a capacitance-to-digital signal converter circuitconfigured to receive a time-varying, analog, capacitance-indicatingsignal from the capacitive sensor and in response provide acorresponding digital signal.

Aspect 9 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 through 8 tooptionally include or use the capacitive sensor or the controllercircuit includes a capacitance-to-digital signal converter circuitconfigured to receive a time-varying, analog, capacitance-indicatingsignal from the capacitive sensor and in response provide acorresponding digital interrupt signal indicating that a value of amagnitude of the capacitance-indicating signal exceeds a specifiedreference capacitance value.

Aspect 10 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 through 9 tooptionally include or use an environment sensor, and wherein thecapacitive sensor is configured to update a baseline capacitancecharacteristic using information from the environment sensor about anenvironment of the article.

Aspect 11 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 through 10 tooptionally include or use a timer circuit, and wherein the capacitivesensor is configured to calibrate itself at a fixed interval accordingto a signal from the timer circuit.

Aspect 12 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 through 11 tooptionally include or use a dielectric member disposed between theelectrodes and the upper surface of the insole, the dielectric memberhaving a relative permittivity that is higher than the relativepermittivity of air.

Aspect 13 can include or use, or can optionally be combined with thesubject matter of Aspect 12, to optionally include or use the dielectricmember including an open cell foam member.

Aspect 14 can include or use, or can optionally be combined with thesubject matter of Aspect 12, to optionally include or use the dielectricmember including a closed cell foam member.

Aspect 15 can include or use, or can optionally be combined with thesubject matter of Aspect 12, to optionally include or use the dielectricmember including a neoprene member.

Aspect 16 can include or use, or can optionally be combined with thesubject matter of Aspect 12, to optionally include or use the dielectricmember including a ceramic member.

Aspect 17 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 1 through 16 tooptionally include or use the dielectric member configured to occupy agap between a top surface of the electrodes and a bottom surface of afoot when the foot is present inside the article.

Aspect 18 can include or use subject matter (such as an apparatus, asystem, a device, a method, a means for performing acts, or a devicereadable medium including instructions that, when performed by thedevice, can cause the device to perform acts), such as can include oruse an article of footwear, comprising a tensioning member, a motorizedtensioning device for controlling tension of the tensioning member, atleast one capacitive sensor for receiving information about a presenceor absence of a foot within the footwear, and a control unit, whereinthe control unit can receive information from the at least onecapacitive sensor and thereby determine whether a foot is present,absent, entering, or exiting the footwear. In Aspect 18, the controlunit can conditionally operate the motorized tensioning device using theinformation from the at least one capacitive sensor, the control unitcan powers down (e.g., turn off) the motorized tensioning device whenthe information indicates a foot is absent or exiting the footwear,and/or the control unit can operate the motorized tensioning device whenthe information indicates a foot is present or entering the footwear.

Aspect 19 can include or use, or can optionally be combined with thesubject matter of Aspect 18, to optionally include or use an insole, andwherein the at least one capacitive sensor is disposed at or near anupper surface of the insole proximal to a foot when the article is worn.

Aspect 20 can include or use, or can optionally be combined with thesubject matter of Aspect 19, to optionally include or use the at leastone capacitive sensor disposed in an arch region of the insole.

Aspect 21 can include or use, or can optionally be combined with thesubject matter of Aspect 19 or 20, to optionally include or use adielectric member configured to occupy a gap between a top surface ofthe at least one capacitive sensor and a bottom surface of the foot whenthe foot is present and seated against the insole in the footwear.

Aspect 22 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 19 through 21 tooptionally include or use the at least one capacitive sensor includes asubstantially planar substrate with at least two spaced apart conductorsdisposed thereon.

Aspect 23 can include or use, or can optionally be combined with thesubject matter of Aspect 22, to optionally include or use the at leasttwo spaced apart conductors including respective conductive traces thatare arranged in parallel along the substrate.

Aspect 24 can include or use subject matter (such as an apparatus, asystem, a device, a method, a means for performing acts, or a devicereadable medium including instructions that, when performed by thedevice, can cause the device to perform acts), such as can include oruse an article of footwear comprising a capacitance-based foot presencesensor configured to generate a capacitance-indicating signal indicativeof a presence, or a relative location, of a foot inside of the articleof footwear, the capacitance-based foot presence sensor including a pairof interleaved electrodes disposed on a common substrate, and aprocessor circuit configured to receive the signal from the footposition sensor and, when the signal indicates a presence of a foot orindicates a change in a relative location of the foot in the article offootwear, the processor circuit is configured to initiate datacollection from one or more other sensors in or associated with thearticle of footwear, and/or to actuate a drive mechanism to tighten orloosen the article of footwear about the foot.

Aspect 25 can include or use, or can optionally be combined with thesubject matter of Aspect 24, to optionally include or use the footpresence sensor configured to generate a signal indicative of a changein a mutual capacitance characteristic associated with the electrodes.

Aspect 26 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 24 or 25 tooptionally include or use a dielectric insert member provided between atleast a portion of the foot presence sensor and the foot when thearticle is worn, wherein the dielectric insert member has a relativepermittivity that is greater than a relative permittivity of air.

Aspect 27 can include or use, or can optionally be combined with thesubject matter of Aspect 26, to optionally include or use the dielectricinsert member comprising neoprene.

Aspect 28 can include or use, or can optionally be combined with thesubject matter of one or any combination of Aspects 24 through 27 tooptionally include or use the processor circuit configured to update areference or baseline capacitance characteristic of the sensor when aninsole is added to or removed from the article of footwear.

Each of these non-limiting Aspects can stand on its own, or can becombined in various permutations or combinations with one or more of theother Aspects or examples described herein.

Various Notes

The above description includes references to the accompanying drawings,which form a part of the detailed description. The drawings show, by wayof illustration, specific embodiments in which the invention can bepracticed. These embodiments are also referred to herein as “examples.”Such examples can include elements in addition to those shown ordescribed. However, the present inventors also contemplate examples inwhich only those elements shown or described are provided. Moreover, thepresent inventors also contemplate examples using any combination orpermutation of those elements shown or described (or one or more aspectsthereof), either with respect to a particular example (or one or moreaspects thereof), or with respect to other examples (or one or moreaspects thereof) shown or described herein.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In this document, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein,” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, composition, formulation, or process that includes elements inaddition to those listed after such a term in a claim are still deemedto fall within the scope of that claim. Moreover, in the followingclaims, the terms “first,” “second,” and “third,” etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

Geometric terms, such as “parallel”, “perpendicular”, “round”, or“square”, are not intended to require absolute mathematical precision,unless the context indicates otherwise, instead, such geometric termsallow for variations due to manufacturing or equivalent functions. Forexample, if an element is described as “round” or “generally round,” acomponent that is not precisely circular (e.g., one that is slightlyoblong or is a many-sided polygon) is still encompassed by thisdescription.

Method examples described herein can be machine or computer-implementedat least in part. Some examples can include a computer-readable mediumor machine-readable medium encoded with instructions operable toconfigure an electronic device to perform methods as described in theabove examples. An implementation of such methods can include code, suchas microcode, assembly language code, a higher-level language code, orthe like. Such code can include computer readable instructions forperforming various methods. The code may form portions of computerprogram products. Further, in an example, the code can be tangiblystored on one or more volatile, non-transitory, or non-volatile tangiblecomputer-readable media, such as during execution or at other times.Examples of these tangible computer-readable media can include, but arenot limited to, hard disks, removable magnetic disks, removable opticaldisks (e.g., compact disks and digital video disks), magnetic cassettes,memory cards or sticks, random access memories (RAMs), read onlymemories (ROMs), and the like.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to complywith 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Also, in the above Detailed Description,various features may be grouped together to streamline the disclosure.This should not be interpreted as intending that an unclaimed disclosedfeature is essential to any claim. Rather, inventive subject matter maylie in less than all features of a particular disclosed embodiment.Thus, the following claims are hereby incorporated into the DetailedDescription as examples or embodiments, with each claim standing on itsown as a separate embodiment, and it is contemplated that suchembodiments can be combined with each other in various combinations orpermutations. The scope of the invention should be determined withreference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

1. A system comprising: a first sensor configured to sense a bodyposition, wherein the first sensor includes an insulating substrate andat least two spaced apart electrodes on the substrate; and an gapfilling member disposed between a surface of the first sensor and acavity configured to receive the body, wherein the gap filling member isconfigured to influence a responsiveness of the first sensor to a changein the body position.
 2. The system of claim 1, wherein the gap fillingmember has a relative permittivity characteristic that is greater thanthe relative permittivity of air.
 3. The system of claim 2, wherein thegap filling member comprises neoprene.
 4. The system of claim 1, furthercomprising an article of footwear, wherein the first sensor is coupledto the footwear and configured to sense a foot location or a footproximity relative to the first sensor.
 5. The system of claim 4,wherein the electrodes extend across a portion of a plane of an insoleof the article of footwear.
 6. The system of claim 5, wherein theelectrodes are disposed adjacent to a foot arch portion of the insole.7. The system of claim 1, further comprising a signal generatorconfigured to provide an electric signal to the electrodes, wherein theelectrodes are configured to provide an electric field in response tothe electric signal, and wherein the first sensor is configured toprovide information about the sensed body position based on changes inthe electric field.
 8. The system of claim 7, further comprising anarticle of footwear, wherein the first sensor is coupled to anunder-foot portion of the article of footwear.
 9. A method comprising:providing an excitation signal to electrodes of a first sensor, thefirst sensor configured to sense a body position relative to a surfaceof the first sensor, and the electrodes being spaced apart on a sharedsubstrate; and receiving a response signal from the first sensor inresponse to the excitation signal, wherein a magnitude of the responsesignal is influenced by a dielectric characteristic of a gap fillingmember that is disposed between the surface of the first sensor and acavity configured to receive the body.
 10. The method of claim 9,further comprising providing the gap filling member having a relativepermittivity that is greater than the relative permittivity of air. 11.The method of claim 9, wherein the response signal indicates a change ina position of a foot in an article of footwear.
 12. The method of claim9, further comprising processing the response signal, using a processorcircuit, to identify at least one of a footwear donning event or afootwear doffing event.
 13. The method of claim 9, further comprisingprocessing the response signal, using a processor circuit, to identify amagnitude of a change in a position of a foot in an article of footwear.14. The method of claim 13, further comprising conditionally actuatingan automated lacing engine based on the identified magnitude of thechange in the position of the foot.
 15. An article of footwearcomprising: a motorized tensioning device for controlling a position ofa tensioning member; a first sensor configured to sense a foot positioninside a cavity of the footwear, wherein the first sensor includes aninsulating substrate and at least two spaced apart electrodes on thesubstrate; an gap filling member disposed between a surface of the firstsensor and the cavity of the footwear, wherein the gap filling member isconfigured to influence a responsiveness of the first sensor to a changein the foot position; and a processor circuit configured toconditionally actuate the motorized tensioning device based oninformation from the first sensor about the foot position.
 16. Thearticle of footwear of claim 15, wherein the processor circuit comprisesa signal generator configured to provide an alternating current drivesignal to the electrodes of the first sensor, and wherein the electrodesare configured to generate an electric field in the cavity in responseto the drive signal.
 17. The article of footwear of claim 15, whereinthe first sensor is configured to sense a change in the foot positioninside the cavity of the footwear.
 18. The article of footwear of claim15, wherein the processor circuit is configured to use information fromthe first sensor to determine a presence or an absence of the foot fromthe cavity of the footwear, and the processor circuit is configured toactuate the motorized tensioning device based on the determined presenceor absence of the foot.
 19. The article of footwear of claim 15, whereinthe electrodes are disposed at or adjacent to a foot-facing surface ofan insole of the article of footwear.
 20. The article of footwear ofclaim 15, wherein the electrodes are disposed at or adjacent to a footarch-receiving portion of the article of footwear.